Furnace Installation & Replacement

When it is time to replace

Most gas furnaces last somewhere around 15 to 20 years. Age alone is not a reason to replace one, but age plus a costly repair usually is. A cracked heat exchanger, repeated failures over a couple of winters, rooms that never get warm and gas bills that climb with no change in use are the usual signs. If your furnace is older and the repair would cost a large share of a new one, we give you both prices and let you decide.

80% or 95% efficiency

Furnace efficiency is measured as AFUE, the share of the fuel's heat that ends up in your house. A standard furnace is about 80% AFUE and sends hot exhaust up a metal flue, often shared with the water heater. A high-efficiency, or condensing, furnace is 90% AFUE or higher. It pulls extra heat out of the exhaust, which cools it enough to vent through plastic pipe out a side wall or the roof, and it produces water that has to drain away. A condensing furnace costs more to install and less to run. Switching from one type to the other can mean new venting, a drain and sometimes a liner for a water heater left alone in the old chimney. We include all of that in the quote.

Sizing and ductwork

Many furnaces in older homes are bigger than the house needs. A Manual J load calculation tells us how much heat your home loses on a cold night, and we size the new furnace to match. A right-sized furnace runs longer, quieter cycles and keeps rooms more even. We also look at the ducts and the return air. A new furnace on undersized or leaky ducts will still struggle, and fixing a restricted return is often a cheap way to make the whole system work better.

Set up for altitude

Furnace ratings assume sea level. At the elevations around Denver, each cubic foot of air holds less oxygen, and gas appliances have to be set up for it. Manufacturers publish high-altitude instructions, which usually call for smaller gas orifices or adjusted gas pressure, and the furnace's output goes down to match. We follow those instructions, measure the gas pressure and combustion, and size the furnace with the reduced output in mind.

Permit, inspection and install day

A furnace replacement needs a mechanical permit in most cities and counties across Denver Metro, and we pull it. Most installs take one day. We protect the floors, remove the old furnace, set the new one and connect the gas, venting, drain and ductwork. Then we test for gas leaks and carbon monoxide, check the temperature rise, set up the thermostat and show you how to change the filter. The inspector checks the work after we finish, and you get the records for your files.