Skip to content
heatpump.blue

Find the outdoor temperature where your heat pump stops saving you money.

For your weather, your exact model and your rates. Then see what your current thermostat setting is costing you.

Free · No account · Anywhere in the US

Backup heatHeat pump
Your lockout: ? °F
Diagram: below your lockout temperature your backup heat runs; above it, your heat pump. The tool finds where that line should be for you.
Find my lockout temperatureHow it works

Your setting in four questions

About a minute. Everything else starts from a sensible default you can change.

Four questions. Everything else has a sensible default you can change under Make it more accurate.

Where is the house?
What heats your home?
The furnace burns

Shopping for a heat pump? Compare models on your rates

Which heat pump do you have?

On the outdoor unit, find the silver or white label, usually on a side or back panel. Type what follows MODEL or M/N. The first 6 to 8 characters are enough.
Which thermostat runs it?
So we can tell you the setting in its own words.
°F

Optional. With it, we show what your current setting costs you. Leave it blank if the heat pump never locks out.

Make it more accurateYour rates, fuel price, furnace, home size or bills. All optional.
Electricity price
$per therm

Leave blank to use your state’s average.

Furnace efficiency

Look at the exhaust pipe where it leaves the furnace.

The house
sq ft
How drafty is it?

Free, no account. Your answer is a link you can keep.

Built by UniColorado Heating & Cooling

Three inputs. One temperature.

Your thermostat switches from the heat pump to backup heat at one outdoor temperature. We find the one that costs you least.

  1. 01

    Your weather

    Your local hourly weather history: how many hours each winter you actually spend at every outdoor temperature.

  2. 02

    Your heat pump

    Your exact model’s rated performance, so the answer follows how your unit really behaves as it gets colder.

  3. 03

    Your rates

    Your electricity and backup fuel prices, including time-of-use pricing if you’re on it.

What you get

One lockout temperature with a sensible range, where to set it on your thermostat, and what your current setting costs compared with it. Sometimes the honest answer is “let the furnace take over sooner”.

In every result and chart:Heat pumpBackup heat (furnace, boiler or strips)

Built and run by UniColorado Heating & Cooling

A locally owned HVAC contractor in Denver, founded in 2014. UniColorado built heatpump.blue so any homeowner in the US can set their lockout from real numbers. It works anywhere; UniColorado itself installs only in Colorado.

A Mitsubishi heat pump outside a Denver home, the shrubs around it covered in snow.
Mitsubishi heat pump in a Denver winter. Installed by UniColorado.
A UniColorado pickup parked beside a newly installed heat pump on the side of a red-brick house.
A UniColorado job site.
A Mitsubishi cold-climate heat pump running in falling snow against a brick wall.
Cold-climate heat pump in fresh snow. Installed by UniColorado.
Heat pumps installed in the Denver area
12,000+
Founded in Denver, Colorado
2014

In the Denver metro or on the Front Range?

Take your result to UniColorado for a heat pump or furnace installation, or a second look at your settings. Anywhere else, your result works with any installer.

(303) 250-1000

2700 W Evans Ave #100
Denver, CO 80219

Visit unicolorado.com (opens in a new tab)

More from the .blue family

Free and focused tools, built by the same team.

Questions

What is a heat pump lockout temperature?
The outdoor temperature below which your thermostat stops running the heat pump and heats with your backup instead: a furnace, a boiler or electric strips. Thermostats call it different things, such as compressor lockout, compressor minimum outdoor temperature or switchover temperature.
Is a lower lockout always cheaper?
No. A heat pump gets less efficient as it gets colder, so below some outdoor temperature your backup fuel can cost less for the same heat. Where that happens depends on your weather, your model and your energy prices, which is why one rule of thumb does not fit every home.
Is the lockout the same as the balance point?
No. The balance point is about comfort: the temperature below which the heat pump alone can no longer keep up with your home. The lockout this tool finds is about cost. Your result shows both, labelled separately.
Is it free? Do I need an account?
It is free and there is no account. Your result is a link you can save or send to your installer.
Who built heatpump.blue?
UniColorado Heating & Cooling, a locally owned HVAC contractor in Denver, Colorado, founded in 2014. The tool works anywhere in the US; UniColorado installs only in Colorado.
Does heatpump.blue track me?
Yes. We use Google Analytics, PostHog, umami and Cloudflare to see how the tool is used, so we know what to improve.