A furnace replacement is a chance to fix the problems that came with the old one: uneven rooms, noisy starts, and a gas bill that never seemed right. Summit Heating & Air installs gas furnaces throughout Boise and Boise, Meridian, Nampa, Eagle, and Kuna, from standard efficiency single-stage models to high-efficiency condensing furnaces with variable-speed blowers. We size the furnace with a load calculation, check the ductwork and venting, and confirm the gas line can supply the new unit before we recommend anything. Every installation includes removal of the old furnace, a new unit set on a proper base, sealed connections to the existing plenum, correct venting for the efficiency class, a condensate drain where needed, and a mechanical permit with inspection. We adjust the gas pressure and input for Boise's elevation and verify temperature rise and combustion before we leave. If your air conditioner or heat pump shares the blower, we confirm the match.
Signs your furnace is due for replacement
- The furnace is over 15 years old and repairs are getting frequent
- Some rooms stay cold while the thermostat says the house is warm
- The unit rumbles, bangs, or rattles at startup
- Gas bills climb each winter with no change in habits
- A technician has found a cracked heat exchanger
- The blower runs but the air never feels properly warm
What a furnace installation includes
- Load calculation, duct and return air check, and gas line sizing
- Removal and disposal of the old furnace
- New furnace, sealed plenum connections, and a new filter cabinet where needed
- Venting and condensate drain installed for the efficiency class, with freeze protection where the drain runs cold
- Elevation adjustment, gas pressure setting, and combustion test at startup
- Mechanical permit, inspection, warranty registration, and thermostat setup
How a furnace replacement works with us
- We inspect the current furnace, ducts, venting, and gas supply, and ask how the house heats now.
- You receive a written proposal with two or three furnace options and a fixed installed price for each.
- Our crew removes the old unit, sets the new furnace, connects the plenum, gas, venting, and drain, and wires the thermostat.
- We set the gas pressure for elevation, measure temperature rise, and run a combustion analysis.
- We pull the permit, meet the inspector, register the warranty, and walk you through the filter and thermostat.
Furnace installation cost in Boise
A standard efficiency single-stage gas furnace replacement starts from $4,500 installed in the Boise area, including the permit. High-efficiency condensing furnaces and two-stage or variable-speed models cost more, and a furnace with an electronically commutated blower motor pairs well with an air conditioner or heat pump. Cost also depends on the BTU rating, whether new venting is required, condensate drain routing, and any duct or return air changes. Replacing a furnace and air conditioner together usually costs less than doing them a year apart. We give a fixed written price after the site visit. Financing is available on approved credit.
Furnaces in Boise homes
Boise's elevation of about 2,700 feet means many furnace manufacturers call for a gas input adjustment, and a unit installed without one can overheat, soot, or trip the limit. We handle that on every install. Winter design temperatures near 10 degrees mean the furnace must carry the house through inversion weeks without help. Older North End and Bench homes often have basement furnaces with masonry chimneys that cannot vent a condensing furnace, so we plan the venting before quoting. Homes in Meridian built since 2000 usually have PVC venting already in place, but condensate lines running through a cold garage can freeze. Kuna homes from the same period are set up the same way. We route and insulate those lines properly.
Questions we get about this
Should I choose a standard or high-efficiency furnace?
A high-efficiency condensing furnace uses less gas for the same heat and vents through PVC. It costs more up front and needs a condensate drain. In a house you plan to keep for years, it usually makes sense. In a home with a chimney and no easy drain path, a standard model may fit better.
How long does a furnace installation take?
Most replacements finish in one working day. Jobs that need new venting through a wall or roof, a filter cabinet, or return air changes may take longer. We tell you the plan before installation day so you know what to expect.
Does the new furnace need a permit in Boise?
Yes. Boise requires a mechanical permit for a furnace replacement, and so does every other jurisdiction in Ada County. An inspector reviews the gas connection, venting, and clearances. We pull the permit and meet the inspector. It is part of our price.
Will a new furnace fix my cold rooms?
Sometimes. If the old furnace was undersized or the blower was weak, a properly sized unit with a better blower helps. If the ducts are leaking, crushed, or missing returns, the furnace alone will not solve it. We check the ducts and tell you either way.
What size furnace does my house need?
We run a load calculation using your square footage, insulation, windows, and air leakage, then pick a furnace with the right BTU output after the elevation adjustment. Most Boise homes need 60,000 to 100,000 BTU input. Oversizing wastes gas and causes short cycling.
Do you install furnaces in older homes with no return ducts?
Yes. Many North End homes have a single return in a hallway. We can add return air paths or a larger return drop so the new furnace gets the airflow it needs. We price that as part of the proposal, not as a surprise later.