HVAC SERVICES IN JOHNSTOWN NORTHERN COLORADO

By the team at Homegrown Heating and Air Conditioning.

Every Service We Cover in Johnstown

We work on the whole system, not one appliance:

• AC repair and AC installation
• Furnace repair, and furnace installation and replacement
• Heating maintenance and tune-ups
• Heat pump installation and repair
• Indoor air quality and filtration upgrades
• Whole-home humidifiers
• Ductwork repair and sealing
• Smart thermostat installation
• Ductless mini-splits
• Emergency HVAC repair, same-day, seven days a week, 7 a.m. to 7 p.m.

Three of those carry most of the Johnstown work, and each has its own page: ductwork repair and sealing, furnace installation and replacement, and AC repair.

Johnstown Tightened the Duct Leakage Limit Below the Model Code

Johnstown adopted the 2024 International Codes by Ordinance No. 2025-280, with the codes effective January 1, 2026, and amended the duct testing section as it did so. The adopted list is published on the Town’s building codes page.

The local limit is 4 cubic feet per minute per 100 square feet of conditioned floor area served, with the air handler installed at the time of the test. When the air handler is not installed, the limit drops to 3 cfm per 100 square feet. The model 2024 energy code would allow as much as 6 cfm per 100 square feet for a home over 1,000 square feet with three or more ducted returns and all components installed. A duct system that passes in a neighboring jurisdiction can fail in Johnstown.

Here is what the test involves. The whole duct system, supply and return together, is pressurized to 0.1 inch water gauge, which is 25 Pascals, with the registers taped or otherwise sealed. It can be run as a rough-in test or as a postconstruction test. A written report has to be signed by whoever conducted it and given to the code official. Two exceptions apply: ducts and air handler located entirely inside the building thermal envelope, and small systems serving 1,200 square feet or less, which are allowed 60 cfm or less.

A tighter number changes how ductwork gets detailed, not what equipment goes in:

• Mastic, or a tape listed and labeled for the purpose, on every joint, seam and connection. Not cloth duct tape.
• Boots sealed to the drywall or subfloor, which is where most of the leakage on a retrofit is hiding.
• Plenum and air handler cabinet seams sealed, including the filter rack and the service panel.
• No building framing cavity used as a duct or plenum, which the 2024 energy code prohibits outright.
• R-8 insulation on supply and return duct running outside conditioned space.

We build the test into the bid on Johnstown work rather than discovering the number at final inspection.

Permits and Inspections in Johnstown

Johnstown publishes an explicit permit list, which is unusual and useful. New or replacement water heaters, furnaces and air conditioners each require a permit. A new thermostat does not. Heat pumps, mini-splits and ductwork alterations are not named on the list, so they fall under the general rule that mechanical work requires a permit.

What that means in practice:

• A furnace or air conditioner permit requires a mechanical contractor and an electrical contractor licensed or registered with the Town of Johnstown.
• The inspection on a furnace or AC replacement is a Mechanical Final.
• Inspection requests go through the Town’s online portal by 4:00 p.m. the business day before. An unprepared inspection fails and carries a $50 reinspection fee, so the permit and approved documents have to be printed on site, the address visible and the work area accessible.
• Carbon monoxide detection is required within 15 feet of each separate sleeping area and on each level, which is stricter than the state baseline. Colorado statute separately ties an operational alarm to any permit that replaces a fuel-fired appliance.
• Gas piping is tested at 10 psig, above the model code figure, and plastic fuel gas piping is buried at least 18 inches below grade.

We are licensed and insured, Town of Johnstown license AEC1619, and we file the permit and the inspection request as part of the job. We also pull HVAC permits in unincorporated Weld County, where no contractor license is required.

Xcel Serves Johnstown for Both Electricity and Gas

That combination matters on a heat pump quote. Xcel runs a standard rebate tier and a bonus tier, and the bonus is not available to customers whose primary heating source is an existing electric system. A Johnstown home already buying Xcel gas can generally reach the bonus tier.

Amounts effective October 1, 2026:

• Cold-climate ducted heat pump: $1,500 per heating ton measured at 5 degrees with the bonus, $750 per ton without it.
• Standard ducted air-source heat pump: $600 per cooling ton with the bonus, $300 per ton without it.
• Gas furnace at 95 percent AFUE or better replacing a non-condensing furnace: $225. That one ends January 1, 2027.

Xcel’s air conditioner rebate has already ended and has not applied to invoices dated after January 1, 2024. Separately, we are registered with the Colorado Energy Office, so we claim the Colorado heat pump tax credit and apply it as a discount on the invoice, worth $1,000 on an air-source heat pump in 2026 with at least $333 passed through to you. There is no federal tax credit for a 2026 installation. Rebate figures move, so we at Homegrown Heating and Air Conditioning confirm them at quote time rather than at invoice time.

Sizing Equipment for Johnstown Conditions

Johnstown addresses fall in both Weld and Larimer counties, and the published winter design temperature is around 0 to 1 degree depending on which side of the line you are on. Summer design sits in the low 90s. Those are the numbers a room-by-room load calculation has to hold at.

Duct leakage feeds straight back into sizing. A system losing air into an attic or crawl space delivers less capacity than its nameplate claims, which is how a correctly sized unit still fails to keep up on the coldest morning. Fixing leakage first sometimes means the replacement equipment can be smaller, quieter and cheaper to run.

One correction worth making here: the federal minimum efficiency for a gas furnace is 80 percent AFUE, not 95 percent. A condensing furnace is often the better choice and it is what the Xcel rebate requires, but it is a decision rather than a legal floor.

Next-Day Service When the Cooling Quits

When an air conditioner fails during a hot stretch, everyone calls in the same 48 hours. We hold capacity for no-cooling calls instead of booking the schedule solid, and we send a technician who can diagnose and repair on the same visit where parts allow.

Judy Matthews wrote: “My air conditioner broke during hot weather and they came out the next day. Technician was very courteous and efficient.”

That is the standard we schedule around rather than an exception we made once. Courtesy and efficiency on site are also a training matter: shoe covers, a clean work area, written readings and a clear explanation of what failed and why. Read more customer reviews from Northern Colorado homeowners.

Book HVAC Service in Johnstown

Tell us what the system is doing and how the house behaves room to room, and we will schedule the diagnostic. Contact Homegrown Heating and Air Conditioning to book HVAC services in Johnstown.