Common problem · Same day

Thermostat blank or not responding?

A blank thermostat is scary and usually cheap. Here are the four causes, most common first.

$99 diagnostic, credited to the repair
Same-day across Denver
No overtime fees

Get Help Fast (720) 447-0177

How urgent

Same day if the system is fully off. Often a five-minute fix.

Call if: Batteries and breaker are fine and it’s still blank
Call if: The screen works but the system doesn’t respond
Call if: You smell burning at the furnace

(720) 447-0177

What it usually is

The causes, most common first.

1

Dead batteries

Many thermostats run on AA or AAA batteries. Replace them first.

Free. New batteries.
2

Tripped float switch

The AC drain pan filled and a safety switch cut power to the thermostat. Empty the pan and clear the drain.

Clear the drain, reset the switch
3

Blown low-voltage fuse

A 3-amp fuse on the furnace control board protects the thermostat wiring.

A fuse and a wiring check
4

Furnace door switch

A panel not fully latched cuts the power.

Free. Latch the panel.

Every fix gets a written price before any work. The $99 diagnostic is credited toward it.

Try this first

What to check before you call.

If one of these fixes it, great. If not, you’ve saved us five minutes on the diagnosis.

1
Replace the thermostat batteries.
2
Check the furnace switch and breaker.
3
Make sure the furnace panels are latched all the way.
4
Look for a small plastic switch on the AC drain pan and make sure the pan isn’t full.

Who we are

Hello. We’re Duality.

Duality Heating and Air LLC is a Denver heating and cooling company run by one licensed technician and the people he trusts. We fix furnaces, ACs, heat pumps, and the air in your home, and we do it the way we’d want it done at our own house. Comfort, in perfect balance.

Denver-based

One technician who lives here, not a call center in another state.
Price in writing

You approve the number before we touch a tool. It never changes.
Fix before replace

We repair what can be repaired and show you both numbers when it can’t.

Questions

Thermostat Not Working, answered.

Should I upgrade to a smart thermostat?

If you’re replacing it anyway, yes. Xcel Energy often rebates them and we can install one in under an hour.

From Denver neighbors

HVAC service

Cecilia Gomez
Google review

“Professional, knowledgeable, and incredibly helpful. He took the time to explain everything clearly, answered all of my questions, and made the entire process easy and stress-free. I truly appreciated his honesty, responsiveness, and attention to detail.”
AC repair

Jessica Russman
Google review

“Very honest and reliable. He showed up on time and fixed our old AC after we had several companies try to sell us a new one. We would 1000% recommend Duality to anyone who wants to feel confident they’re dealing with the right company.”

Same-day help