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HVAC Financing Calculator

See the monthly payment, the interest you will pay and the total cost of financing a new heating or cooling system, after any down payment and up-front rebates.

Method reviewed October 25, 2026. Version 1.0.0. How it works

Your inputs

Only amounts that reduce the loan itself. Tax credits you claim later do not.

Result

Monthly payment
$207.54
Total interest
$2,452.10

$207.54 a month for 60 months; $2,452.10 interest in total.

  • Assumes a fixed rate and equal monthly payments with no fees. Promotional “deferred interest” offers can charge all the interest if the balance is not paid in time — read the terms.
Amount financed
$10,000.00
Total of payments
$12,452.10
Total cost incl. down payment
$14,452.10
Show the working
  1. Amount financed = price − down payment − rebates
    $12,000.00 − $2,000.00 − $0.00 = $10,000.00
  2. Monthly rate = APR ÷ 12
    8.99 % ÷ 12 = 0.7492 %
  3. Payment = P × r ÷ (1 − (1 + r)^−n)
    $207.54 × 60 months

How the payment is calculated

For a fixed-rate loan with equal monthly payments, the payment is P × r ÷ (1 − (1 + r)⁻ⁿ), where P is the amount financed, r is the monthly rate (APR ÷ 12) and n is the number of months. This is the standard level-payment formula, and it matches the period-by-period rule in the U.S. Truth in Lending regulation (Regulation Z): each month the balance grows by the interest and falls by the payment, reaching zero with the last payment.

At 0 % APR the payment is simply the amount divided by the months.

Read the offer, not just the payment

  • Deferred-interest promotions (“no interest if paid in full in 12 months”) can charge all the interest back to the start if any balance is left at the end.
  • Fees, insurance and dealer discounts for paying cash change the real cost. The loan’s disclosure shows the APR and the total of payments.
  • A longer term lowers the payment but raises the total interest.

Worked example

These are the example values the calculator opens with, and the result the engine calculates for them.

Inputs

Project price
12,000 $
Down payment
2,000 $
Rebates or credits applied up front
0 $
APR
8.99 %
Term (months)
60

Result

Monthly payment
$207.54
Total interest
$2,452.10
Amount financed
$10,000.00
Total of payments
$12,452.10
Total cost incl. down payment
$14,452.10

$207.54 a month for 60 months; $2,452.10 interest in total.

Assumptions

  • Fixed APR, monthly compounding (monthly rate = APR ÷ 12), payments at the end of each month, no fees.

Limitations

  • Lender fees, insurance and promotional terms change the real cost. Compare the APR and total of payments on the loan disclosure.

Frequently asked questions

Should rebates reduce the amount I finance?

Only if they are applied at the time of sale. A rebate or tax credit you receive months later does not reduce the loan; enter 0 for it here and treat it as money back later.

Is a lower monthly payment better?

Not always. Stretching the same loan over more months lowers each payment but increases the total interest. The calculator shows both so you can compare terms.

What APR should I enter?

The APR on the loan offer or disclosure. It includes interest and certain finance charges, which makes it the fairest single figure for comparing offers.

Sources

  1. Regulation Z (Truth in Lending), Appendix J — Annual Percentage Rate Computations — Consumer Financial Protection Bureau. Each unit-period the balance increases by the finance charge and decreases by the payment; APR = unit-period rate × unit-periods per year.

Spotted an error? Report a problem with this calculator — see our corrections policy.