Frequently Asked Questions
Get your questions answered about solar hot water, heat pumps, incentives and financing options, HeatSmart Nantucket, and more!
- What is a solar hot water system and how does it work?
- What are the benefits of solar hot water?
- What’s the difference between solar hot water and solar PV?
- How long do solar hot water systems last?
- Will my building work for solar hot water?
- When would solar hot water not be recommended?
- Can I use a solar hot water system for space heating as well?
- Can I use a solar hot water system to heat my pool?
- What if I don’t live on Nantucket year-round?
- How complicated is installing a solar hot water system and how much time can it take?
- How well will a solar system work on the Grey Lady?
- Should I be concerned about winter performance?
- What happens if there’s too much heat in the summer? Will my water be too hot if I use solar hot water?
- What equipment is being installed through this program?
- What is an air source heat pump and how does it work?
- What types of air source heat pumps are available?
- What are the benefits of using an air source heat pump?
- Are there drawbacks to air source heat pumps?
- Is an air source heat pump right for me?
- How do I go about selecting an air source heat pump installer?
- Why are air source heat pumps considered “clean heating and cooling” technologies?
- How efficient are air source heat pumps?
- How do the annual maintenance costs of an air source heat pump compare to other heating systems?
- How long do air source heat pumps last?
- How noisy are air source heat pumps?
- Can air source heat pumps provide hot water?
- How complicated is installing a heat pump and how much time will it take?
- How can I maximize energy savings from my heat pump?
- How well do heat pumps work in the middle of winter?
- What rebates and incentives are available to me?
- What financing options are available to me?
- How much could I potentially save by installing clean heating and cooling?
- How much can I expect to pay for a clean heating and cooling system?
- What is HeatSmart Nantucket and who is organizing it?
- How does HeatSmart Nantucket work?
- What is clean heating and cooling and what technologies is HeatSmart Nantucket offering?
- How were the HeatSmart Nantucket installers selected?
- Why isn’t there a HeatSmart air source heat pump installer?
- Why should I participate now?
|What is solar hot water and how does it work?||
Solar hot water (SHW) systems use energy from the sun to directly heat your home or business’ hot water. SHW systems in Massachusetts with good sun exposure can provide up to 80% of your annual hot water usage.
SHW systems are simple and work as described in the infographic below:
|What are the benefits of solar hot water?||
Solar hot water can be a great investment for your home or business.
|What’s the difference between solar hot water and solar PV?||
Solar hot water and solar photovoltaic (PV) systems are two different types of solar energy technologies. Solar hot water uses use thermal energy from the sun to preheat your hot water, while solar PV converts solar energy to electricity.
SHW has been a reliable clean energy option for decades—in fact, the original solar panels President Carter put on the White House were SHW panels!
President Carter inspects a newly-installed solar hot water system on the roof of the White House in 1979 (© 2010 Jimmy Carter Library)
Solar PV and SHW are both reliable clean energy technologies that can save you money and reduce your carbon footprint. While solar PV will offset a bigger portion of your home’s energy consumption, there are a few reasons you might consider SHW in addition to or instead of solar PV:
|How long do solar hot water systems last?||Well-designed and maintained solar hot water systems can last for over 30 years. Some systems installed in the 70s and 80s are still functioning today! In particular, the collectors on your roof can last for over 30 years—and the collectors RES Solar installs have warranties of 10 years. The most frequent maintenance required is changing out the glycol, which may only need to be done once every 5 years or more. Depending on water quality, as is typical of all hot water tanks, the tank may need to be replaced once or twice over the course of the 30-year lifetime, though it is warrantied for 10 years.|
|Will my building work for solar hot water?||
The biggest factor for determining whether solar hot water will work for you is whether you have a space on your roof or in your yard that gets enough sun exposure. Ideally, this site will have 5 hours of unshaded solar access every day. The installation site selected will also need to pass approval from the HDC in order to move forward.
Additionally, if you’re interested in pursuing a roof mount, your roof and shingles will need to be able to support the added weight of SHW collectors. If your roof will need replacement in the next 8 years, you may want to replace your roof before installing solar, as you’ll need to temporarily remove the panels during the roof replacement.
Sign up for a no-cost home assessment from RES Solar! When you sign up for your assessment, RES Solar will do a preliminary screen of whether there may be somewhere on your property that gets enough sunlight through an online tool. If it looks like it may be suitable, the RES team will come by to further evaluate your site and determine whether SHW will be a good fit for you.
|When would solar hot water not be recommended?||
Even if you have a great site for solar hot water, there are some cases where it may not be the best fit for you.
In particular, you need to use hot water to save on water heating! If you’re a single-person household or a seasonal homeowner, you may not use enough hot water for the system to pay back quickly. Additionally, seasonal homeowners who aren’t using the heat generated by their systems year-round will not be eligible for the MassCEC rebate.
Also, if you don’t pay much in federal income taxes (or are non-profit entity), you may not be able to take full advantage of the full 30% federal tax credit.
|Can I use a solar hot water system for space heating as well?||
Yes, solar hot water systems can also be used to provide supplemental heating to your boiler by adding an additional heating coil.
This can be a great option if you’re a seasonal homeowner who needs to keep your home somewhat heated through the winter. Heat from the solar collector will help to offset heat that would otherwise need to be provided by a boiler--and it will make this system eligible for MassCEC rebates!
|Can I use a solar hot water system to heat my pool?||
Yes, pool heating systems are the most common type of solar hot water system installed in the US. While only commercial pools are eligible for MassCEC rebates, even residential pools are among the most cost-effective applications for solar water heating!
|What if I don’t live on Nantucket year-round?||
As noted above, you might not be able to access the available MassCEC incentives—or save enough money on hot water usage to make the investment worthwhile.
However, if you have a pool, a pool-heating solar hot water system will be very cost-effective. Additionally, if you have a boiler in your home, a solar hot water system can be connected to your boiler’s distribution system so that you can use solar generation to offset off-season heating and help keep your pipes from freezing while you’re gone.
|How complicated is installing a solar hot water system and how much time can it take?||
A solar hot water system is pretty straightforward to install and can be completed in 2 or 3 days.
The most “complicated” part of the process will be getting your system approved by the HDC and making sure that you’ve completed all of the steps necessary to receive rebates, tax credits, and 0% interest financing from Mass Save (if needed). RES Solar is very familiar with all of these programs, and NSS has worked with the HDC to permit dozens of SHW installations across the island.
|How well will a solar system work on the Grey Lady?||
Very well! Over 800 homes and businesses have installed solar hot water in Massachusetts since 2011. Despite our particularly gray days, Nantucket still receives only 10% less solar energy than Boston and 35% less than San Diego!
Your system’s production will definitely drop off in mid-winter when sunlight is at its weakest (and at night when the sun isn’t shining), but over the course of the year, a well-sited solar hot water system can still provide up to 75% of your home’s domestic hot water. SHW systems can still generate plenty of heat on overcast days.
|Should I be concerned about winter performance?||
Not at all! Cold Massachusetts winters are the reason why non-toxic glycol antifreeze is circulated through the collectors on your roof. Additionally, RES Solar will install primarily drainback systems for redundant freeze protection. Drainback systems will, when the system turns off, drain all of the glycol into a small reservoir tank (called a “drainback tank”).
Snow may actually melt even faster from a flat plate collector than from your roof! Your collectors will begin collecting sunlight passing through snow. As the collector heats up, it will begin melting snow and increase the rate at which it slides off!
|What happens if there’s too much heat in the summer? Will my water be too hot if I use solar hot water?||
The drainback system described above also helps to prevent the glycol from over-heating once the solar tank has been fully heated up and the sun is still heating your collectors (also known as “stagnation”).
|What equipment is being installed through this program?||RES Solar will install SunEarth flat plate collectors, which is warrantied for 10 years, as is the Rheem solar storage tank that will be installed with your system.|
|What is an air source heat pump and how does it work?||
Air source heat pumps (ASHP)--often known as “mini-splits”--are electric appliances that provide heating and cooling by moving heat into a building (for heating) or out of a building (for cooling). Heat pumps do not create heat like electric resistance heating does; instead, they transfer heat from one place to another. Heat pumps use the outdoor air as a source of heat, while ground source (or geothermal) heat pumps use the ground as a source of heat.
They accomplish this by using a refrigerant that absorbs heat from colder air in order to move that heat into a space with warmer air – much the same way that a refrigerator or air conditioner works except that it can move heat in both directions to provide both heating and cooling.
While heat pumps have been used in the South as central heating and AC systems for decades, new cold climate heat pumps are cutting-edge versions of these systems that are optimized for New England weather. Cold climate heat pumps can continue providing heat even when winter air is well below freezing: today’s cold climate air source heat pumps can extract heat from the air all the way down to -13°F. In the summer, the process is reversed and heat is absorbed from the cooler indoor air and moved to the warmer outdoor air. New ductless heat pump options are available as well for homeowners who don’t have ductwork.
Since it takes far less energy to move heat than it does to create heat, heat pumps are one of the most efficient home heating systems available.
Check out this video from Mass Save, the state's utility energy efficiency program, for a visual explanation of how ductless mini-split heat pumps work (and read on to learn more about the types of heat pumps available!).
|What types of air source heat pumps are available?||
There are two primary types of ASHPs:
Ductless air source heat pumps are exactly as they sound: heat pumps that don't require that you have ductwork in your home to provide heating and air conditioning. Each ductless system includes one outdoor unit connected to one (single-zone) or more (multi-zone) indoor wall, floor or ceiling air distribution units. Ductless ASHPs are often referred to as ductless mini-splits.
Ductless air source heat pumps can be installed as a primary source of heating and cooling or installed to heat and cool specific rooms. This could include, for example, installing ductless units in the most frequently used rooms like family rooms or master bedrooms to displace heating or cooling from your existing system, or placing ductless units in rooms or new additions that never seem to be warm or cool enough.
These systems can be used for heating, cooling, dehumidification or as a fan. Because each indoor unit can be controlled individually, you can reduce your energy use even more by lowering the temperature in rooms that are not being used.
Ducted air source heat pumps have an outdoor unit that is connected to a building's ductwork, which is used to distribute heating or air conditioning throughout the home. Ducted (also known as central or unitary) use your home’s existing ductwork, though not all ductwork is sized adequately for heat pumps. Your installer can tell you if your ductwork is sized adequately and what modifications may be necessary during a free site visit.
Regardless of whether a system is ductless or ducted, all ASHPs will have an outdoor unit (pictured below), which will be mounted on a ground platform or on the side of your home.
Above: A ductless ASHP outdoor unit; Below: A ducted ASHP outdoor unit
This outdoor unit will be connected to one or more indoor air distribution units. If you’re installing a ducted ASHP, this will be a central air handler similar to one used by a furnace or central AC system. If you’re installing a ductless ASHP, this will typically be a wall-mounted unit (pictured below).
For homeowners that might not have suitable wall space or don’t like the aesthetic look of the wall-mounted indoor unit, floor-mounted and ceiling-mounted units are also available, though these units cost more to install. Photo courtesy of E. Armstrong
|What are the benefits of using an air source heat pump?||
There are many reasons why an air source heat pump could be a good fit for your home:
|Are there drawbacks to air source heat pumps?||
While heat pumps are a great fit for many Nantucket homes and businesses, like other heating and cooling systems they have a few drawbacks:
|Is an air source heat pump right for me?||
There are few homes where some heat pump solution might not work. However, if you answer “Yes” to any of the questions below, a heat pump system could be a particularly good fit for you:
|How do I go about selecting an air source heat pump installer?||
HeatSmart Nantucket decided to not select an air source heat pump installer for the program, opting to make the HeatSmart opportunity available to the variety of businesses already installing heat pumps on the island.
Check out our resources and list of MassCEC rebate-eligible installers for suggestions on who to work with and who to select to serve your home or business.
|Why are air source heat pumps considered “clean heating and cooling” technologies?||
Air source heat pumps are considered to be “clean” heating and cooling systems because they do not create heat, but rather they move heat from the ambient air from one place to another. This process is powered by electricity, which can also be sourced from renewable sources like solar, wind, or hydro.
Even though our grid is only about 12% renewable today, a heat pump system powered by grid electricity will still reduce your greenhouse gas emissions from heating by 40-60%! These emissions will continue to decrease from year to year as our grid becomes greener, whereas the emissions from fossil fuels will stay the same.
|How efficient are air source heat pumps?||
Heat pumps are typically rated for heating efficiency based on their Heating Seasonal Performance Factor (HSPF) or seasonal Coefficient of Performance (COP), both of which describe the system’s efficiency over the course of the heating season. The seasonal efficiency of heat pumps can range from 220% to 300%+ (i.e. COP of 2.2 to 3.0+) depending on the system type and application. That means that for every one unit of electricity used, 2.2 to 3 units of heat are transferred into the home. By comparison, electric resistance heating has a COP of 1.
Heat pumps also provide efficient cooling, comparable to highest-efficiency air conditioners. Ductless heat pumps can give you the opportunity to get AC throughout your home without using loud window units!
|Why should I consider a cold climate air source heat pump?||
Heat pumps have been widely installed throughout the South and Mid-Atlantic states for decades, though these systems have typically not performed well in New England: heat pumps extract heat from the air, and as the temperature outside drops, the available heat also drops, making it harder for the heat pump to meet your increasing home heating load and causing it to rely on an inefficient electric resistance backup.
Newer cold climate models are optimized for colder winter performance (without sacrificing cooling efficiency), are tested for their performance and efficiency at 5°F and can provide heat below -10°F—well below the lowest recorded temperature on Nantucket.
If you're interested in using a heat pump as a primary source of heating—and are interested in saving on your heating bill—we recommend installing a cold climate heat pump to ensure that you can get high-efficiency performance and comfort year-round. Only cold climate models are eligible for MassCEC rebates, and the size of these rebates typically cover the higher costs and more.
If you're only interested in using a heat pump for cooling (e.g. you don't have ductwork but want air conditioning or are a seasonal homeowner), a cold climate model may not be necessary. High-efficiency ductless heat pump models can still receive rebates from Mass Save even if they're not cold climate, so we encourage you to ask your installer about high-efficiency, rebate-eligible models even if you're not interested in year-round performance.
|How do the annual maintenance costs of an air source heat pump compare to other heating systems?||Annual system maintenance, which consists of cleaning air filters and an annual maintenance checkup for the outside unit, costs about the same as annual servicing charges for a boiler or furnace.|
|How long do air source heat pumps last?||Heat pumps have an expected lifetime of about 15 years—similar to the average furnace or central AC system.|
|How noisy are air source heat pumps?||A ductless indoor unit is quieter when running than a refrigerator and much quieter than a typical window AC unit. High-efficiency, variable-speed ducted heat pumps are quieter than a typical furnace or central air conditioner.|
|Can air source heat pumps provide hot water?||
There are water heaters that use heat pump technology (heat pump water heaters or HPWH), but they are considered different technologies than the air source heat pumps included in the HeatSmart Nantucket program.
If you’re interested in cheaper, cleaner hot water, consider a solar hot water system!
|How complicated is installing a heat pump and how much time will it take?||
A heat pump installation is typically a straightforward process with minimal disruption to your home once the Historic District Commission approves your installation and your installer pulls the necessary permits. A simple, single-zone ductless heat pump system can be completed in less than a day and only requires a single 2-3 inch hole to be cut (and later, sealed) in your wall.
If you are installing a “multi-zone” ductless system or a ducted system that requires modifications to your ductwork, your installation may take a few days to complete. Additionally, if your system needs extra time to minimize aesthetic impacts, it may take more time to run piping through walls.
|How can I maximize energy savings from my heat pump?||
While most heat pump systems work right out of the box, there are a few things you may want consider to get the most out of your system:
|How well do heat pumps work in the middle of winter?||
Quite well! While traditional, non-cold climate heat pumps struggle in freezing weather, the newer cold climate heat pumps promoted through HeatSmart Nantucket are designed to be used in a New England winter, providing efficient heating all the way down to 5°F while still continuing to provide useful heat all the way down to -13°F or lower.
On some of the colder days, your heat pump might not put out as much heat and you may need to use some backup heat to help stay warm. As such, the installer will keep your existing heating system in place (or install a backup) for the coldest days of the year.
Additionally, you will want to keep the outdoor unit of your heat pump system clear of snow to make sure it has sufficient airflow--just like you need to keep your furnace vents clear to prevent carbon monoxide build-up.
Nervous about heat pump performance in January? Don't be: Mainers and Vermonters have installed more cold-climate heat pumps than any other New England states in the past few years—over 30,000 since 2013—and both Maine and Vermont are significantly colder than Massachusetts in the winter!
|What rebates and incentives are available to me?||
There are a variety of incentives available for clean heating and cooling offered by the Massachusetts Clean Energy Center (MassCEC), Dept. of Energy Resources (DOER), and Mass Save. Consult the HeatSmart Nantucket rebates and financing guide for a description of these rebates and any special requirements, and speak with your installer to learn more about how to access these incentives.
These incentive programs include the following:
|What financing options are available to me?||
The Mass Save HEAT Loan is available to residents of Nantucket. The HEAT Loan offers a 0% interest, 7-year loan of up to $25,000 and is available for both CH&C technologies. That equates to monthly payments of about $120 for a $10,000 system! Note that you only get one Mass Save HEAT Loan—but you can finance more than one improvement on one loan. Consider completing incentivized home weatherization activities and installing a heat pump and/or solar hot water system at once! You also need to have completed a home energy assessment in the previous two years to be eligible for the HEAT Loan.
Some heat pump installers may also offer financing separate from the Mass Save HEAT Loan. Ask about what other options may be available to you.
|How much could I potentially save by installing clean heating and cooling?||
Everyone’s heating (and cooling) bill is different, so the amount you could save on energy will vary depending on a number of factors, including what fuel you currently use to heat your home and hot water, how well insulated it is, what size and shape your home is, what temperature you keep your thermostat at, how many heat pump units or solar hot water collectors you install, and more.
For solar hot water, a well-sited system can reduce your hot water bill by up to 75%. Hot water accounts for about 20-25% of the typical Massachusetts home heating bill, and with the high cost of heating water with propane, oil, and electric resistance, you can expect for year-round energy savings from a well-sited solar hot water system to pay for the cost of the system in as little as 5 years. Seasonal homeowners may not use enough hot water to have sufficient energy savings to cover the cost of a solar hot water system for domestic hot water. However, if you are a seasonal homeowner with a pool, consider getting evaluated for a solar pool heating system, which can significantly reduce your pool heating bill.
For heat pumps, the most important factor on how much you'll save is what fuel you currently use to heat your home and how old and inefficient your heating system is. If you heat with electric resistance, or propane, you’ll probably see the most energy savings—anywhere from $500 a year to over a thousand or more, depending on how much you currently pay and how much of your heating bill you offset. Seasonal homeowners that aren’t around in the winter won’t see much in the way of heating savings, but high-efficiency heat pumps are still more efficient than many older central air conditioners and window units.
One way to compare these different CH&C technologies to fossil fuel-based equipment is to look at how much it costs to provide a unit of heat. It is hard to predict fossil fuel prices from year to year, but based on fuel prices today, heat pumps will heat your home at approximately half the cost of propane, 40% of the cost of electric resistance, and 70-80% of the cost of oil. Take a look at the chart below for a closer look.
Solar hot water is not listed above because solar-heated water is virtually free! Your water heating bill will simply be reduced proportionally by the amount of hot water provided by the solar hot water system.
|How much can I expect to pay for a clean heating and cooling system?||
Solar hot water: You can expect to pay approximately $6,000 after incentives for a solar hot water system. Consult RES Solar's pricing guide here.
Heat pumps: The cost of a heat pump will vary depending on the type of system installed (ductless or ducted), how many zones you want to heat/cool, the size of your home, and more. In general, a ductless heat pump will cost roughly $4,000 or more for every zone of your home you want to heat.
|What is HeatSmart Nantucket and who is organizing it?||
HeatSmart Nantucket is a community-based education, outreach, and group purchasing program for clean heating and cooling technologies. HeatSmart Nantucket seeks to offer residents and businesses the opportunity to reduce their energy costs and carbon emissions by adopting energy efficient heat pump and solar hot water systems.
From May through November 2018, residents and businesses in Nantucket will have the opportunity to learn more about these energy-saving technologies—and purchase solar hot water systems at a special HeatSmart price from RES Solar. Throughout the duration of this program, HeatSmart Nantucket will offer educational “meet the installer” workshops and open houses to give you the chance to learn more about the technologies being promoted, and which offerings might be best suited for you.
HeatSmart Nantucket is the latest community-driven, town-supported, clean energy initiative on the island. HeatSmart Nantucket is led by the Town’s Energy Coordinator, Lauren Sinatra, with support from a team of volunteers and other town officials. HeatSmart Nantucket is a pilot program offered through HeatSmart Mass, a statewide program supported by the Massachusetts Clean Energy Center (MassCEC) and Massachusetts Department of Energy Resources (DOER).
|How does HeatSmart Nantucket work?||
HeatSmart Nantucket aims to help Nantucket residents and businesses to save on their energy bills and take advantage of a wide range of state and utility incentives for clean heating and cooling technologies. HeatSmart offers educational content and the opportunity to learn more about and connect with installers of clean heating and cooling technologies. For solar hot water, HeatSmart Nantucket offers a straightforward, hassle-free approach to purchasing a solar hot water system from our competitively-selected installer, RES Solar.
The process for working with RES is simple:
|What is clean heating and cooling?||
In cold climates like Massachusetts, heating and cooling accounts for over 30% of the greenhouse gas emissions that contribute to climate change. Reducing emissions from heating and cooling will be necessary for the state to meet its legally-binding target of reducing emissions by 80% below 1990 levels by 2050. In 2014, the Commonwealth released a statewide strategy for increasing the adoption of clean heating & cooling (also known as “renewable thermal”) technologies.
Clean heating and cooling (CH&C) describes high-efficiency heating and cooling technologies that can use thermal energy (or be powered by energy) derdived from renewable sources--including the sun, air, earth, and sustainably-harvested bioenergy. Because of their importance to meeting our state climate goals, state and local governments and utilities across the state are offering thousands of dollars in incentives to support their adoption.
There are other CH&C technologies (e.g. geothermal heat pumps, modern wood heating, biodiesel) available. Learn more about them here.
|How were the HeatSmart Nantucket installers selected?||
Interested installers were invited to submit bids through a competitive, public request for proposal to participate in HeatSmart Nantucket (as well as the three other HeatSmart Mass Pilot communities) in November of 2017. In January and February, the HeatSmart Nantucket committee evaluated proposals with support from technical experts.
For solar hot water, the HeatSmart Nantucket team selected RES Solar, who will be supported by local installer Nantucket Solar Solutions to serve HeatSmart Nantucket participants. RES with support from Nantucket Solar Solutions will be able to offer Nantucket residents and businesses a unique combination of experience installing solar on-island, recognized expertise installing solar hot water across the Commonwealth, and a strong record of customer service.
|Why isn't there a HeatSmart air source heat pump installer?||
While the HeatSmart Nantucket team solicited and reviewed proposals from heat pump installers, the Nantucket team ultimately decided that participation in this program should be available to the range of qualified on- and off-island contractors. Moreover, the hundreds of initial interest leads the Nantucket Energy Office received for heat pumps would be challenging for only one installer (or a even a few) to keep up with while still providing you with the responsive, high-quality service that HeatSmart Nantucket hopes to deliver.
As HeatSmart Nantucket is focused on ensuring that Nantucket residents can benefit from the year-round energy savings offered by cold climate heat pumps—and the extensive rebates offered by the state—HeatSmart Nantucket recommends working with any of the installers qualified by MassCEC to offer cold climate heat pump rebates. Learn more about these installers and recommended questions to ask potential installers here.
|Why should I participate now?||
There’s never a better time to save money on energy (and reduce your carbon footprint!), particularly with oil and propane prices back on the rise. Sign up for HeatSmart Nantucket today to take advantage of the limited-time incentives for CH&C technologies offered by the utility and state and federal government.
The HeatSmart pricing offered for solar hot water is a limited time offer only. Only customers who sign contracts with RES by November 30, 2018 will receive this special pricing.