Can you help me troubleshoot cooling for my garage?

It’s against Building Codes which include Mechanical & Fire Codes to run a duct into your garage from the house.

Have you looked into a “mini split”? They’re very effective and they can’t be that much $, as I see them all over the place in Mexican cities.

Cheryl,

Thanks for the input. In case you don't know, Virginia is not within sight of any Mexican city, at least that's what my GPS tells me. Also, I bought my house to live and die in, so unless I have the Fire Inspector over for a beer no one will be the wiser.

Like Cheryl says. It's not legal, not safe. It also would totally imbalance the whole system. Violation of building codes, homeowners insurance. If anything happened to the garage or home. Your health and well being can be affected.

The Building Codes are technically called Health & Safety Codes and here’s Why garages are a concern:

There’s “combustibles” in there- oil, gas, possibly propane and others.

There’s off gassing of chemicals in there- the combustibles themselves, plus fertilizer, pesticides, & herbicides - are often stored in garages.

This is why the door from the garage into the house is supposed to be a 1-hour Fire-rated gasketed self-closing-hinges door.

In newer houses and additions the entire garage is supposed to be finished in Type-X drywall, because of fire protection.

A HVAC duct from the garage makes an excellent tunnel for fumes and fire itself, back into a home. 🔥

What I was saying with the Mexico analogy is that if mini split units are all over Mexico, they must be cheap.

I looked on HD’s & eBay’s site’s and a 9000BTU 12SEER unit is $400. They are cheap for being able to both heat & cool.

The BTU’s/SEERS/Price go up from there in all criteria. Think “new hotel room HVAC system.”