Littleton, CO Heating System Replacement — HVAC Guide

Estimated Read Time: 9 minutes

If your old heater is noisy, unreliable, or driving up energy bills, it is time to plan a gas furnace replacement. The right system will keep your family warm, lower costs, and improve air quality. In this guide, our Denver team explains how to choose the best replacement without overspending. You will see what really matters, what to avoid, and how to get professional results you can rely on all winter. Limited-time savings inside.

1) Signs it is time to replace your gas furnace

A good system should keep you comfortable without surprises. If you see these warning signs, start planning a replacement before the first hard freeze.

• Age 15 to 20 years or more, especially with rising repair frequency.
• Uneven rooms or longer run times to reach temperature.
• Loud operation, rattling, or a burner flame that is yellow instead of blue.
• Rising energy bills even after tune-ups.
• Cracked heat exchanger diagnosis or repeat safety shutoffs.

Waiting until a complete failure can force a rushed decision at the worst time. A planned replacement lets you compare options, secure financing, and schedule an install that fits your calendar. It also helps you protect your ductwork, thermostat, and air quality investments by coordinating everything at once.

Pro tip for Front Range homes: weather can swing 30 degrees in a day. A right-sized, properly staged furnace smooths out temperature swings and prevents short cycling.

2) Right-sizing your furnace the professional way

Bigger is not better. Proper sizing starts with a Manual J load calculation that considers square footage, insulation, windows, orientation, and infiltration. Your ductwork capacity and condition also matter. A restrictive or leaky duct system can waste the output of a new furnace and create noise or hot-cold spots.

• Load calculation: determines BTUs required at winter design temperature.
• Duct evaluation: static pressure, leakage, and register balance.
• Altitude: at Denver’s elevation, gas appliances are derated due to thinner air. Licensed pros account for this when sizing and setting gas pressure.
• Home upgrades: air sealing, insulation, and window improvements can reduce the needed furnace size.

Oversized furnaces short cycle, wear out parts faster, and cost more to run. Undersized furnaces struggle on the coldest nights. The sweet spot is a unit that meets the load with some reserve, paired with a blower that can actually move the air through your ducts.

3) Efficiency explained: AFUE, stages, and blower technology

Efficiency impacts comfort and lifetime cost. Here is what to weigh as you compare models.

• AFUE rating: Annual Fuel Utilization Efficiency. A 95% AFUE furnace converts 95% of fuel into heat. High efficiency units often require PVC venting and a condensate drain.
• Single-stage vs two-stage vs modulating: two-stage and modulating furnaces run longer on low heat for steadier comfort and better humidity control in shoulder seasons. They are quieter and reduce temperature swings.
• ECM variable-speed blowers: use far less electricity than PSC motors and boost comfort by circulating air gently between calls for heat.
• Sealed combustion: pulls outside air for combustion, improving safety and reducing drafts.

Match AFUE with your goals. If you plan to own the home for 7 to 10 years, higher AFUE and ECM can pay back through lower gas and electric use. Regular maintenance can save up to about 30% on energy compared to neglected systems, so plan your tune-ups.

4) Venting, safety, and code compliance

A safe installation starts with the venting category your home supports.

• Standard efficiency typically vents to a lined chimney or metal flue.
• High efficiency condensing furnaces use PVC venting and produce condensate that must be drained and trapped.
• Combustion air: ensure proper intake air or sealed combustion to prevent backdrafts.
• Gas line capacity and pressure must be verified, especially if you add a larger furnace or other gas appliances.
• Carbon monoxide detectors are essential near sleeping areas and on each level.
• Permits and inspections: replacements require permits in most municipalities. This protects your warranty and insurance.

A licensed crew will handle permits, follow manufacturer specifications, set gas pressure, verify draft, and document readings. After start-up, we test safety controls and verify temperature rise is within rating plate specs. That is how you know the system is performing as designed.

5) Comfort features and indoor air quality upgrades

Modern furnaces do more than heat. Pair the system with controls and IAQ add-ons that improve comfort and health.

• Smart thermostats: schedule, geofencing, and remote control. Many can optimize staging and blower speeds.
• Whole-home humidifiers: reduce dry air, help protect wood floors, and can make 68 degrees feel like 70.
• Advanced filtration and air purification: electronic air cleaners, UV germicidal lights, and high-MERV options that trap fine dust and allergens. Balance filtration with duct capacity to avoid static pressure problems.
• Zoning: room-by-room control with multiple dampers and thermostats for large homes or additions.

Fix-it 24/7 offers humidifiers, air purifiers, and UV lights that pair with high efficiency furnaces. Our technicians disassemble, clean, and inspect components that other companies never touch, which helps these add-ons perform their best.

6) Total cost of ownership: price, warranties, and financing

Upfront price is only part of the story. Consider these parts of total cost.

1. Equipment and install labor: varies by AFUE, staging, blower type, and venting changes.
2. Ductwork improvements: sealing and corrections can boost comfort and efficiency.
3. Thermostat and IAQ add-ons: factor long-term value, not just initial cost.
4. Energy use: higher AFUE and ECM blowers reduce gas and electrical consumption.
5. Maintenance: regular tune-ups protect the warranty and reduce breakdowns.

Ask about rebates and financing. Fix-it 24/7 offers transparent, flat-rate pricing and financing options through partners such as Wells Fargo and GreenSky, subject to approval. We back installations with a 100% satisfaction guarantee and our A+ BBB reputation. If you enroll in our Green Club Membership, you get priority scheduling and discounts on repairs and replacements to keep lifetime costs low.

7) Repair vs replace: a simple decision framework

Not every problem requires a new furnace. Use this quick guide to decide.

• Age under 12 years with minor issues: repair, then schedule maintenance.
• Cracked heat exchanger or repeated safety failures: replacement for safety.
• Repair cost more than 50% of replacement and the unit is past 12 years: replacement.
• Comfort complaints that persist after repairs or duct fixes: consider two-stage or modulating upgrade.

If you are facing frequent igniter failures, blower motor noise, or control board errors, we can test the system and give you a flat-rate estimate for both paths. We also provide free replacement estimates, so you can compare the math before you choose.

8) What to expect on installation day

A well-run install protects your home and your new warranty.

• Arrival review: your lead technician confirms scope, permits, and thermostat preferences.
• Protection: floor covers and clean work zones to keep your home tidy.
• Removal: safe decommissioning and haul-away of the old furnace.
• New install: set equipment, update venting, gas line, and electrical as required.
• Start-up and testing: measure static pressure, gas pressure, and temperature rise. Verify staging and airflow.
• Walkthrough: thermostat training, filter schedule, and warranty documents.

Most replacements take one day. Complex duct or vent changes may take longer. We offer 24/7 emergency service, so if your system fails during a cold snap, we can stabilize heat and schedule a rapid replacement. Some service areas offer a 4-hour response window for emergencies.

9) Why Denver homeowners choose Fix-it 24/7

You need a contractor who owns the outcome, not just the sale. Fix-it 24/7 Plumbing, Heating, Air & Electric serves the Denver metro and nearby cities with a customer-first approach.

• Certified pros: EPA and NATE certified, licensed and insured.
• Proven trust: A+ BBB rating, thousands of 5-star reviews, and industry awards.
• Straightforward pricing: flat-rate quotes and financing options.
• Full-service: furnaces, heat pumps, boilers, ductwork, thermostats, and IAQ.
• Membership value: Green Club Membership is just $29.95 per month and includes year-round maintenance benefits and discounts.

We tailor systems to our climate and altitude. Our team sizes equipment correctly for Front Range homes, corrects duct issues, and sets up smart controls for consistent comfort. From free replacement estimates to post-install tune-ups, we stand behind every job.

Special Offers for Denver-Area Homeowners

• Save $500 on HVAC replacement installation. Limited time. May not be combined with other offers.
• Save $1,000 on a new full HVAC system installation. Restrictions apply.
• Green Club Membership: only $29.95 per month. Year-round HVAC maintenance, priority service, and up to 25% off HVAC repairs.
• Lafayette residents: $39 Furnace Tune-Up and Deep Clean. Ideal for pre-replacement checks.

Call 303-536-1616 or visit https://fixmyhome.com/ to claim your offer when you schedule your estimate.

What Homeowners Are Saying

"I received the most thorough cleaning of my furnace I have ever experienced. Jose dismantled the entire insides of the furnace and after cleaning the parts looked brand new. He gave me maintenance tips and introduced me to the electronic air filter that can take the place of the disposable pleated air filters."
–Debbie, Furnace Cleaning

"Extremely pleased with the quality and professionalism of the team that came to my home to do a heating system cleaning and maintenance. Jose and Sheel were so nice and personable while completing the job. They took care to keep my home clean while they worked and kept me informed throughout the process."
–Gary D., Heating Maintenance

"Jose from Fixit 24/7 was the best HVAC service tech I've ever had. He did a thorough job tuning up our furnace, much better than the company who originally installed the system 11 years ago and did a tune up a few years ago. Jose was well trained and clearly communicated what he found. I'll call back and ask for him next year."
–Gary L., Furnace Tune-Up

"When our home heating system boiler started knocking and making loud noises, Fit-it 24/7 was able to get me a quick next day appointment during the coldest winter weather! ... Keith was back the following day installing a new combi boiler system for our house and stayed the entire day until 6:00 pm installing it to perfection! I highly recommend Fix-it 24/7 Golden and their team!"
–Greg J., Boiler Replacement

Frequently Asked Questions

How do I know what size furnace I need?

A licensed contractor should perform a Manual J load calculation and inspect your ductwork. This accounts for home size, insulation, windows, and altitude to pick the correct BTU output.

Is a 95% AFUE furnace worth it in Denver?

Often yes. High AFUE with an ECM blower lowers gas and electric use. If you plan to stay 7 to 10 years, the energy savings and comfort upgrades usually justify the higher price.

Can I replace my furnace without changing the ducts?

Sometimes, but only if ducts are sized and sealed correctly. Many comfort issues come from ducts. A quick test of static pressure and leakage guides the decision.

How long does a gas furnace replacement take?

Most installs finish in one day. Complex venting or duct changes may add time. Your crew should review timing during the estimate.

Do you offer financing and maintenance plans?

Yes. We offer financing options through partners like Wells Fargo and GreenSky, plus a Green Club Membership at $29.95 per month with priority service and discounts.

Conclusion

Choosing the right gas furnace replacement comes down to accurate sizing, smart efficiency upgrades, and a safe, code-compliant install. For expert help in Denver, Aurora, Lakewood, Thornton, Arvada, Boulder, Westminster, Centennial, Lafayette, and Longmont, call Fix-it 24/7. Get a free replacement estimate, clear pricing, and strong warranties.

Call to Schedule

Call 303-536-1616 or visit https://fixmyhome.com/ to schedule your gas furnace replacement in the Denver metro. Ask about $500 off installation or $1,000 off a full system and our $29.95 Green Club Membership for long-term savings.

Call 303-536-1616 now or schedule online at https://fixmyhome.com/. Mention current offers to redeem $500 off installation or $1,000 off a full HVAC system. Protect your comfort and budget today.

Fix-it 24/7 Plumbing, Heating, Air & Electric is Denver’s trusted home services partner. Our EPA and NATE certified technicians deliver flat-rate pricing, 24/7 emergency service, and a 100% satisfaction guarantee. We hold an A+ BBB rating and are recognized with Angie’s List Super Service and HomeAdvisor Top Rated honors. From furnace replacements to IAQ upgrades, we do it right the first time. Ask about our Green Club Membership for priority service and savings across the Front Range.