The house visit is where an installer works out how much heat your house needs through the coldest week of a Denver winter.
What gets measured
A load calculation starts with your house: the insulation in the walls and ceiling, the windows, how much air leaks in, and the basement. It's run for Denver's elevation and winter design temperature, and the answer is how much heat the house loses on that day. The installer then reads the manufacturer's performance tables to see how much heat a model puts out in the cold, and plans the backup heat for the days below that. The tonnage in a model number is a cooling rating and tells you little about January.
What else the visit should cover
- The furnace room. Venting, the gas line, the drain and room for the new coil.
- The ducts. The size of the return and anything that chokes the airflow.
- The outdoor spot. Where snow drifts, where the roof drips, and how far the line set runs.
- The panel. Room for a new circuit, or whether it needs an upgrade.
What new equipment won't fix
A bigger unit won't cool the upstairs bedroom that has always run warm. That's a duct problem, or a job for a small mini-split in that room, priced on its own.
How we size
We size from a published method and a measured visit. You can ask for a Manual J load calculation for your house, and the estimate lists exact model numbers.
Send photos to start, or walk through all nine steps.
Common questions
Can I see the load calculation?
Yes. Ask for the Manual J after the visit. Any installer should be able to show you theirs.
Why do three installers quote three different sizes?
They usually entered different numbers for the windows, insulation or air leakage. Ask each one what they used, since the house is the same for all three.
Do you size for Denver's altitude?
Yes. Thin air changes how the equipment performs, and any Denver installer should account for it.