The altitude-sizing note
Sizing a system for 6,000 feet
Equipment is rated near sea level. Colorado Springs sits about a mile higher, and some of our towns sit well above that.
Thin air carries less oxygen and less heat in every cubic foot. A gas flame needs a different input, a coil moves less heat, and a fan moves air that is lighter than the chart assumes. None of this is exotic. It is in the installation manuals. It just has to be read, and the equipment set to match.
What we check on every replacement
A load calculation, room by room, before any equipment is chosen
The maker's altitude data for the model we propose
Furnace input and any high-altitude kit, per the manual
Vent size and combustion air checked for the elevation
Duct airflow measured, not assumed
A combustion test at start-up, with the results left with you
Side by side
A sea-level pick against one made for this elevation
| Picked from a sea-level chart | Sized for 6,000 feet | |
|---|---|---|
| Furnace input | Picked from a sea-level chartLeft at the factory setting | Sized for 6,000 feetSet to the maker's altitude table, with a kit where the manual calls for one |
| Cooling size | Picked from a sea-level chartMatched to the old unit or to square footage | Sized for 6,000 feetChosen from the load calculation, then checked against altitude data |
| Vent and combustion air | Picked from a sea-level chartAssumed from the old install | Sized for 6,000 feetChecked for the elevation and the house |
| Airflow | Picked from a sea-level chartAssumed from the equipment label | Sized for 6,000 feetMeasured at the ducts after the work |
| Start-up | Picked from a sea-level chartTurned on to see that it runs | Sized for 6,000 feetCombustion tested and the readings left with you |
Approximate elevation
The higher the town, the more it matters
~5,500 ft
Fountain~6,000 ft
Colorado Springs~6,900 ft
Monument~9,100 ft
Divide
Rounded figures for the town centers. Your street may sit higher or lower.
Questions
About altitude and your equipment
Was my old furnace set up for altitude?
We can check. The label gives the model and input, and the manual gives the altitude table. If it was installed without the kit or the setting, we tell you what we find.
Does altitude change which furnace I should buy?
It changes what we check, and sometimes which kit or setting goes with it. It rarely changes the make. Efficiency, venting and the size of the house still decide most of it.
Is a bigger air conditioner the answer to thin air?
No. An oversized unit cycles on and off, cools unevenly and wears faster. We size from the load calculation and use altitude data to confirm, not to add tonnage by habit.
Do heat pumps work at this elevation?
Cold-climate models do. How well one carries a house through a Front Range winter depends on the house, which is why we calculate the load first and often keep the furnace as backup.
Do I need a carbon monoxide alarm?
Yes, on every level that has a bedroom. If an alarm sounds, get everyone outside and call 911 before you do anything else.
Want the numbers for your house?
The visit covers the load, the equipment and the elevation, and the quote lists all three.