Which is better for a Tucson home, an ERV or an HRV?
For a home on the Tucson valley floor, an ERV (energy recovery ventilator) is usually the better fit, and Climate Pros Tucson can match you with a licensed pro to confirm it for your house. Both devices bring in fresh outdoor air and push stale indoor air out. They differ in what they pass between the two airstreams. An HRV moves heat only. An ERV moves heat and moisture.
Tucson’s heating load is mild: about 1,333 heating degree days a year against 3,424 cooling degree days (1991-2020 normals at Tucson International Airport). An HRV earns its keep by saving winter heat, and Tucson has little winter heat to save. An ERV helps in the long cooling season, because it keeps part of the outdoor heat and moisture from riding in with the fresh air.
Why does moisture matter here?
Tucson air is dry most of the year. At the airport, average dew points sit in the 20s for most of the year and jump into the high 50s in July and August. During the monsoon (June 15 to September 30, the window the National Weather Service uses), outdoor air carries a lot more water. A plain exhaust-and-intake setup hauls that moisture indoors and your AC has to remove it.
An ERV transfers some of that moisture back out before the air enters the house. The benefit shows up in monsoon weeks. In dry months the difference is small.
Do you need ventilation at all?
Older, leaky houses get fresh air by accident. A tightly built house does not. Tucson’s adopted energy code, the 2024 IECC with City of Tucson amendments, calls for residential air leakage testing by an approved certifier such as RESNET or BPI. A house that tests tight needs a planned way to bring in fresh air.
What the code requires for your project depends on the address and the scope of work. Ask the pro whether ventilation is required, or only recommended, for yours.
What changes in a dusty climate?
Dust storms occur during the monsoon. The intake is the weak point. Ask about:
- A filter on the intake, and how often it needs changing.
- Where the intake sits, away from the condenser’s discharge and ground-level dust.
- Whether the unit’s core can be cleaned or has to be replaced.
A clogged intake filter cuts airflow and the unit stops doing its job. Plan on checking it more often than a standard return filter. The indoor air quality service page covers the related options.
ERV vs HRV at a glance
| ERV | HRV | |
|---|---|---|
| Moves heat | Yes | Yes |
| Moves moisture | Yes | No |
| Fit for Tucson’s cooling season | Better | Limited |
| Fit for a Mount Lemmon cabin | Question for the pro | Often considered |
Mount Lemmon and Summerhaven sit in code climate zone 5B with a 4F winter design temperature, so heat recovery matters more there. See HVAC in Mount Lemmon and Summerhaven.
Questions to ask the matched pro
- Is a ventilator required for this project, or an option?
- ERV or HRV, and why for this house?
- Does it tie into the ducts or run on its own?
- Who handles the permit and the air leakage test?
Related reading: indoor air quality for dust, smoke and pollen, whole-home air purifiers, and monsoon humidity and your AC. The full area overview is on the Tucson HVAC hub.
Getting ventilation sized
If you’re building tight or fixing a stuffy, dusty house and want ventilation sized right, you need a licensed pro to look at the house. Call (520) 353-2520 and we’ll match you with a licensed local pro.