0% Interest, $0 Down: Financing a Heat Pump Water Heater with a Mass Save HEAT Loan

A Reservoir heat pump water heater installs for as little as $47/month, $0 down, financed at 0% interest over 7 years through the Mass Save® HEAT Loan program. Depending on the type of water heater you’re switching away from, the monthly fuel savings could be even more than the monthly loan payment.

Let us repeat that: with some kinds of old water heaters, you could save more each month than what you pay toward the loan. The upgrade can be cash-flow positive immediately.

Read on to learn how the program works and whether your water heater is costing you even more than a brand-new one.

About the Mass Save HEAT Loan program

The Mass Save HEAT Loan is a 0% interest financing program offered by Massachusetts utility companies (Eversource, National Grid, and others) to help homeowners pay for energy-efficiency upgrades, including heat pump water heaters. Homeowners can borrow up to $25,000 with no interest and no fees, then repay it in fixed monthly installments over a term of up to 7 years.

Because there's no interest, you pay back exactly what you borrow, nothing more.

The loan stacks on top of rebates offered by Mass Save and the New England Heat Pump Accelerator, and since Reservoir applies all available rebates directly to your quote, your loan amount is the post-incentive price.

How to finance your Reservoir with a HEAT Loan

1. Confirm eligibility

   1. Get a free Home Energy Assessment. This is required to secure the loan. Book through one of Mass Save’s partners. Typically, these are in person, but our partner SeeAir offers an online assessment option.

   2. Get a quote from Reservoir. Start the process with our no-commitment Virtual Assessment.

2. Get the loan

   1. Apply for the loan. Apply at MyHeatLoan.com. You will upload your quote from us as part of the application.

   2. Get approved. Mass Save issues an Authorization Form to you. You then submit it to a participating lender, who runs a standard credit check and approves your loan.

3. Get hot water

   1. We install your water heater. Once you’re approved, we install your water heater, and you start saving money immediately.

   2. You transfer the loan amount to us. Your lender mails a check made out to both you and Reservoir. Once the install is done, you sign it over to us. That's the actual payment for your project.

   3. Your monthly payments begin. You repay the fee to the lender, with zero interest. You only have to pay for what you borrowed.

What are you switching from?

Not every water heater costs the same to run, so not every switch saves the same amount. Here's how Reservoir typically compares, month to month, against what you might have now.

Fuel savings by switching to Reservoir

* Assuming typical use for a household of four and utility prices in Boston, MA in winter 2026: $0.30 per kWh for electricity, $5.67 per gallon for oil, and $3.86 per gallon for propane.

If your current water heater is a non-heat pump electric tank, or fueled by oil or propane, you can save every single month on fuel.

Note: today, natural gas is typically inexpensive enough that savings would be negligible. There are plenty of other reasons to choose to go electric, from indoor air quality to the climate impact, and Reservoir is packed with great features that make your home safer and more comfortable.

Electric resistance: the no-brainer case

If you have an electric resistance tank and expensive electricity, switching to Reservoir could be cash-flow-positive for you immediately. Let’s dive into the math.

The monthly cost to operate your water heater depends on how much energy it uses and the cost of that energy.

To figure out how much you’re paying to heat water, you’ll first need your electric rate, which you can find on your bill, and is usually listed as cents per kilowatt-hour (kWh). Then, look up the energy used by your particular water heater model. This is usually reported as energy used in a full year, so divide by 12 to get monthly electricity use. Last, multiply that monthly use by your electric rate.

With an electric resistance tank heater, you are likely paying between $55 and $175 per month for hot water, whereas with Reservoir, you will likely pay between $25 and $80 per month.

Monthly cost to operate an electric resistance water heater

Monthly cost to operate Reservoir

Looking at the difference between these two tables, you could save between $32 and $96 on your electric bill every month by switching from an electric resistance tank to a Reservoir.

Of course, the cost of switching to a new product can’t be counted out. That’s where the financing option comes in. With a 7-year, $0 down, 0% interest loan, the $3,950 Reservoir Core can have as low as a $47/month loan payment, and a $4,940 Reservoir Max would be $59/month.

The upshot: if you have an electric resistance water heater and your electricity costs more than $0.25 per kWh (as it does in most places in MA), upgrading to a Reservoir starts saving you money immediately. Even including the purchase price.

What to know before you start

It’s a great deal, but there are a few things to remember:

• It's a loan, not a rebate. The interest rate is 0%, but you're still committing to a monthly payment for 7 years, not receiving free money.

• There is a lot of paperwork. Between the assessments, the intake form, the loan application, and the lender application, you'll fill out several forms and share personal financial details, including your Social Security number and employment information. This is typical for loans of this size, but requires some legwork on your part.

• This program is not set in stone. Eligibility, the incentive amount, and loan terms are set by Mass Save and can change; confirm current terms when you apply.

• Fuel savings depend on what you're switching from. As the table above shows, the case is strongest coming off electric resistance, oil, or propane; less so coming off efficient natural gas.

• Only available in MA. Other lenders like Wisetack offer financing, but HEAT Loans are only in Massachusetts. 

The fastest way to know what you'd actually save is to run the numbers on your specific water heater. Get started with our five-minute Virtual Assessment and let us know you’re interested in HEAT Loans. We’d be happy to walk you through the process.