Denver’s 24/7 heating & AC experts
Comfort, in perfect balance.
Same-day furnace and AC repair by a Denver tech. Upfront pricing. A real person answers 24/7.
5.0 · 12 Google reviews, all five stars · 12 five-star reviews
- 5.0 12 Google reviews, all five stars ↗
- NATE CertifiedNorth American Technician Excellence
- BBB A+ RatingBetter Business Bureau
- LENNOX We service
Lennox systems - We service
Trane systems
What We Do
Heat. Cool. Breathe.
Every season, one call.
Furnaces, air conditioners, heat pumps, mini splits, and the air inside your Denver home. Every brand. Every install sized for a mile of altitude.
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Furnace repair, replacement, and $99 tune-ups. Same-day, any brand, sized for Denver altitude.
Learn more about Heating -
AC repair and new systems, heat pumps, and mini splits. Fast dispatch when it quits on a hot day.
Learn more about Cooling -
Humidifiers, filtration, purifiers, and duct sealing. Breathe easier through dry winters and smoke season.
Learn more about Indoor Air Quality -
Low-NOx furnaces, cold-climate heat pumps, ENERGY STAR equipment. We file your Xcel rebates.
Learn more about Green Energy
Straight prices
Three things.
$99 each.
No “starting at.” No fine print. The diagnostic is credited toward the repair if you go ahead with it.
Every other job gets a written, flat-rate price before we start. The number you approve is the number on the invoice. How pricing works
- $99
Seasonal Tune-Up
A full inspection and tune before the season hits. We clean, adjust, test, and write down what we found.
Book it - $99
Emergency Diagnostic
We find the real problem, show it to you, and put the fix in writing before touching a tool. 24 hours a day.
Book it - $99
Indoor Air Quality Check
We measure particles, humidity, and pollutants, then hand you a plain report with the fixes that matter.
Book it
The Duality Promise
Just neighbors
helping neighbors.
Duality is one Denver technician and the people he trusts. No sales reps on commission. No call center in another state. You get the person who quoted the job, on time, with boot covers on.
Heat and cold. Repair and replace. Two sides, kept in balance. That's the name, and it's the job.
Meet the owner
- Denver-Based Owned and run by your neighbor. Not a chain.
- Upfront Pricing Written price before work. It never changes.
- Fix It First We repair what can be repaired. Then we advise.
- Clean Colorado Efficient equipment. Lower bills. Cleaner air.
Real Denver neighbors
Five stars
feel different
here.
12 Google reviews, all five stars. Every one is public: read them on Google, not just here.
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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.”
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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.”
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Jake Henriksson
Google review“Punctual, communicative, and extremely professional without being a corporate robot. He tells the truth and gets things done. And he’s a one-man team, so things aren’t going to get lost in translation. 100% recommend.”
Which door are you at?
Fix it. Replace it. Protect it.
Whichever one you pick, the rest is the same: written price, same-day, a neighbor who answers.
Not ready to book? Each door has a free tool. No email, no account.
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Fix it
Something’s broken. We find it for $99, write the price, and usually fix it the same visit.
Get it fixed -
Replace it
It’s old, loud, or expensive to run. A free estimate shows repair next to replace, with rebates applied.
Get an estimate -
Protect it
Nothing’s wrong yet. A $99 tune-up or a Comfort Plan keeps it that way through the season.
Book a tune-up
Licensed, Bonded & Insured
A Real Colorado Company.
On Paper and on Your Doorstep.
Duality Heating and Air LLC is a locally owned company at 3940 S Hazel Ct, Englewood, CO 80110 that carries the license, bond, and insurance every homeowner should ask for. Ask to see them. We'll show you before we start.
- Colorado LLC
- Licensed
- Bonded
- Insured
- NATE-Certified
- EPA 608 Certified
Service Area
From Golden to Aurora, Castle Rock to Thornton.
All Payments
Pay the tech on site or from your invoice link. Financing with approval in minutes.
- Cash
- Check
- Visa
- Mastercard
- American Express
- Discover
- Apple Pay
- Google Pay
- Zelle
- Venmo
- Financing
All Brands
If it heats or cools a Denver home, we work on it. Factory-trained on the big names, experienced with the rest.
- Lennox
- Trane
- Carrier
- Bryant
- Rheem
- Ruud
- Goodman
- Amana
- American Standard
- York
- and every other brand
Talk to a Denver neighbor
Call, text, or email. A real person answers.
Based in Englewood, serving all of Denver. Open 24 hours, including holidays. No phone tree, no call center.
3940 S Hazel Ct, Englewood, CO 80110Why Duality
The Neighborhood Hero, Not the National Chain.
Big-company polish. Small-business honesty. Here’s what that looks like when a Denver neighbor shows up at your door.
 Duality | Others | |
|---|---|---|
| Pricing | Upfront, flat-rate quote before any work starts. | A quote that can grow once the work starts. |
| Who answers | A real Denver dispatcher, 24/7. The owner is one call away. | A call center, often out of state. |
| Repair vs. replace | We fix what can be fixed and tell you honestly when it can’t. | Replacement tends to come up early. |
| Your home | Boot covers, drop cloths, and a spotless cleanup. Every visit. | A cleanup that’s left to you. |
Takes less than 30 seconds. A real person calls you back.
Resources
Homeowner FAQ.
Straight answers to the questions Denver homeowners ask us most.
All QuestionsDo you really answer 24/7?
Yes. A Denver-based dispatcher answers nights, weekends, and holidays, and emergency visits never carry overtime rates.
How does transparent pricing work?
After diagnosing the problem we give you a written, flat-rate quote before any work starts. The price you approve is the price you pay.
What forms of payment do you accept?
All of them: cash, check, Visa, Mastercard, American Express, Discover, Apple Pay, Google Pay, Zelle, Venmo, and financing through our lending partner. You can pay the technician on site or from the invoice link.
Which brands do you work on?
All of them. Lennox, Trane, Carrier, Bryant, Rheem, Ruud, Goodman, Amana, American Standard, York, Daikin, Mitsubishi, Fujitsu, Bosch, Navien, Rinnai, and every other brand you will find in a Denver home. If it heats or cools a house, we service it.
What areas do you cover?
The greater Denver metro, from Golden to Aurora and Castle Rock to Thornton: Denver, Lakewood, Aurora, Englewood, Littleton, Arvada, Westminster, Thornton, Centennial, Highlands Ranch, Wheat Ridge, Golden, and Castle Rock.
Are you licensed and insured?
Yes. Duality Heating and Air is a Colorado LLC that is licensed, bonded, and insured. Every technician is NATE-certified, EPA 608 certified, and background-checked. You get a text with your tech's name and photo before they arrive.
Comfort Reminders
Never miss a tune-up again.
A short note when it’s time for the fall furnace tune-up, the spring AC check, and the monthly filter check, plus a few Denver-specific tips each season. No sales blasts. Unsubscribe any time.
- A nudge in September and April, before the rush
- A filter-check nudge every month
- Rebate deadlines and cold-snap tips, Denver only
Right now in Denver · October
Deep cold. If the furnace short-cycles or the flame looks yellow, call. Keep the filter fresh.
The driest month. Static and nosebleeds mean low humidity; a whole-home humidifier fixes it.
Shoulder season. The best time to book the furnace repair you’ve been putting off: no rush, no line.
Spring AC check month. A tune-up now beats a no-cooling call in July.
The first hot days are coming. Clear the outdoor unit, change the filter, run the AC once.
Heat arrives. If the AC runs all afternoon and never catches up, call before the heat wave.
Peak cooling. Ice on the lines means turn it off and call.
Smoke season. A MERV-13 filter catches what a standard one lets through.
Fall furnace tune-up month. Book before the first freeze and skip the October rush.
First freeze. Test the heat once before you need it. Check the CO detector batteries.
Heating season. Change the filter, open the vents, and book anything that sounded wrong.
Holiday cold snaps. We answer 24/7 and never charge overtime, even on the 25th.