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
Your setting in four questions
About a minute. Everything else starts from a sensible default you can change.
Three inputs. One temperature.
Your thermostat switches from the heat pump to your furnace or other heat at one outdoor temperature. We find the one that costs you least.
- 01
Your weather
Your local hourly weather history: how many hours each winter you actually spend at every outdoor temperature.
- 02
Your heat pump
Your exact model’s rated performance, so the answer follows how your unit really behaves as it gets colder.
- 03
Your rates
Your electricity and furnace 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 pumpFurnace or other heat (boiler, strips)
Installing in Colorado: UniColorado Heating & Cooling
A locally owned HVAC contractor in Denver, founded in 2014, and heatpump.blue’s sister company in UniCo Group. heatpump.blue works anywhere in the US; UniColorado installs only in Colorado.



- 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.
2700 W Evans Ave #100
Denver, CO 80219
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 furnace or other heat instead: 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 furnace 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 runs heatpump.blue?
DotBlue LLC, a UniCo Group company. The tool is free and works anywhere in the US. UniColorado Heating & Cooling, a sister company in Denver, 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.