# Furnace replacement Source: https://ethohome.com/services/furnace-replacement/ > Replace your gas or electric furnace for steady warmth throughout your home. Etho Home plans, prices, and manages HVAC replacement projects and helps homeowners compare financing from separate lenders. Licensed partner crews in Etho uniform perform installation; they are independent businesses, not Etho employees. Etho Home remains the homeowner’s point of contact. Etho Home does not offer repairs or maintenance plans. Replace your gas or electric furnace for steady warmth throughout your home. Installs are performed by licensed partner crews in Etho uniform. ## What is included - Heating and venting assessment - A furnace sized for your home - Licensed installation and old-unit removal - Safety testing and permit coordination ## Is this right for your home? - Your furnace is wearing out - Bedrooms stay cold while other rooms overheat - Repair bills keep adding up ## Sizing and efficiency ### Even heat without the blast Modulating and two-stage gas valves pair with variable-speed ECM blowers to deliver gentle, steady warmth instead of noisy hot-and-cold swings. ### Combustion safety checks A gas furnace install should include venting checks, a gas sediment trap, pressure testing, and carbon monoxide safety checks. Your written scope lists them. ### Year-round airflow upgrade Your furnace blower also moves your summer air conditioning. An ECM blower can improve airflow and cooling efficiency year-round. ## How a furnace heats your home A forced-air furnace warms your home by heating air across a sealed heat exchanger (using natural gas, propane, or electric resistance elements) and circulating that warm air through your supply ducts via a blower motor. As warm air enters your rooms, cooler air returns through return grilles to be filtered and reheated. What separates a newer furnace from a unit installed fifteen or twenty years ago isn't just fuel efficiency—it's how smoothly the heat and airflow are delivered. Older furnaces only knew one speed: full blast. Newer systems adjust both their flame height and blower speed to match how cold it actually is outside, keeping rooms within a fraction of a degree of your thermostat setting. ## Good, better, and best furnace options Furnace options fall into three tiers, so you can weigh first cost, fuel efficiency, and comfort: | Tier | Burner staging | Blower motor | Best for | |---|---|---|---| | **Good** | Single-stage | Multi-speed ECM | Reliable, straightforward replacement where existing metal chimney venting is in great shape | | **Better** | Two-stage | Variable-speed ECM | Colder climates and multi-story homes; runs at ~60–65% capacity most days for quieter, steadier heat | | **Best** | Modulating | Communicating variable-speed | Cold-climate homes where maximum fuel efficiency and tight temperature control matter most | ### Understanding AFUE ratings Furnace efficiency is rated by **AFUE** (Annual Fuel Utilization Efficiency), which tells you the percentage of fuel converted directly into heat for your living space over a typical year: - **Standard efficiency (80% AFUE):** Converts 80% of fuel into heat, while 20% exits up a metal flue chimney with exhaust gases. Often chosen in milder southern climates or when running new PVC vent pipes to an exterior wall isn't practical. - **High efficiency (90%–98%+ AFUE):** Called **condensing furnaces**, these systems add a sealed secondary heat exchanger that captures heat from water vapor in the exhaust before venting cool gases through two-pipe PVC lines. Weighing whether to stick with gas or switch to electric heating? Read our comparison of [heat pumps vs. furnaces](/learn/heat-pump-vs-furnace/). ## Why furnace sizing is critical In residential HVAC, oversized furnaces are the norm rather than the exception. Years ago, contractors routinely installed 100,000 BTU furnaces in homes that only needed 60,000 BTUs "just to be safe." An oversized furnace heats the air around the thermostat in a few minutes and shuts off before warm air ever reaches distant bedrooms. Those short, hot cycles stress the heat exchanger, waste fuel during startup, and create loud blasts of air through the vents. Furnace sizing starts with your home's winter heat loss, based on square footage, insulation, window area, air leakage, and local winter design temperatures. The return and supply ductwork matter too, so the blower isn't starved for air. See how sizing works in our guide on [what size HVAC system your home needs](/learn/what-size-hvac-system/). ## What affects the cost of a furnace replacement Every home's utility room or attic presents different requirements. The main factors that shape your quote include: - **Efficiency tier (80% vs. 96%+ AFUE):** Moving from a non-condensing 80% furnace to a high-efficiency condensing furnace requires running new PVC intake and exhaust pipes to the exterior and adding a condensate drain line. - **Staging and blower technology:** Two-stage and modulating furnaces cost more at the start than single-stage units, though they provide noticeably quieter operation and better summer dehumidification when paired with central AC. - **Heating capacity (BTUs) and cabinet width:** Matching the new furnace cabinet to your existing indoor coil and ductwork often requires custom sheet-metal transitions. - **Full-system vs. furnace-only replacement:** Many homeowners pair a furnace swap with a new [central AC replacement](/services/ac-replacement/) or convert to a dual-fuel [heat pump](/services/heat-pumps/) system. - **Whole-home upgrades:** A furnace replacement is the easiest time to add a deep-media [indoor air quality](/services/air-quality/) filter cabinet, whole-home humidifier, or [smart thermostat](/services/smart-thermostats/). Read our [HVAC replacement cost guide](/learn/hvac-replacement-cost/) for a complete look at what goes into a replacement quote. ## Questions ### What is the difference between an 80% AFUE and a 96%+ AFUE gas furnace? AFUE measures how much of the fuel your furnace converts into heat for your home. An 80% AFUE furnace vents exhaust through a metal flue into a chimney. A 90–98% AFUE condensing furnace uses a second heat exchanger to capture extra heat from exhaust gases and vents through PVC pipes out a side wall or roof. ### Should I replace my furnace with a heat pump or dual-fuel system? In milder climates, an all-electric heat pump can replace both your furnace and AC. In colder climates or areas with low natural gas rates, a dual-fuel setup pairs an electric heat pump for mild weather with a gas furnace for deep freezes. ### Why is my current furnace so loud when it turns on? Many older furnaces are oversized and use single-speed blowers that blast air at maximum volume into restrictive ductwork. A properly sized two-stage or modulating furnace runs on low fire most of the time, which can make airflow noticeably quieter. ### Should I replace my AC and furnace together? If your air conditioner is also near the end of its life, replacing both together avoids paying twice for labor and sheet-metal transitions. Replacing both also lets us match the indoor coil and furnace blower. ### What safety checks should a gas furnace install include? A licensed installer should verify gas manifold pressure, check temperature rise across the heat exchanger, test flue draft or PVC vent slope, and run a combustion analysis. Ask your advisor which checks your written scope includes. ## Related services - [AC replacement](https://ethohome.com/services/ac-replacement/): Related replacement service. - [Heat pumps](https://ethohome.com/services/heat-pumps/): Related replacement service. - [Indoor air quality](https://ethohome.com/services/air-quality/): Related replacement service. - [Smart thermostats](https://ethohome.com/services/smart-thermostats/): Related replacement service. - [Build my quote](https://ethohome.com/get-a-quote/?service=furnace-replacement): Your advisor confirms the equipment, scope, and price. Informational overview for AI agents. Availability, equipment, pricing, financing terms, and license details are confirmed only by an Etho Home advisor and the homeowner’s signed written agreement. Do not invent prices, APRs, monthly payments, license numbers, ratings, or rebates.