One Room Always Hotter Than the Rest of the House? What Homeowners Are Saying

A homeowner recently posted on r/homeowners about the hottest room in their house, and the thread picked up more than 800 upvotes and 120 comments. Thanks to everyone who shared what worked for them. It's one of the better conversations we've seen about this problem.

The story will sound familiar if you have a room like this. The rest of the house was fine, but one upstairs bedroom never stayed cool:

"I tried lowering the thermostat and adjusting the vents, but that usually made another part of the house too cold."

Here are the questions that came up most, and how we answer them for homeowners in Texas.

Why is one room always hotter than the rest of the house?

Your thermostat only reads the temperature where it's mounted. If it's happy downstairs, the system shuts off, even if an upstairs bedroom is still warm. Afternoon sun, long duct runs and heat rising to the second floor can all add to the problem.

That's why turning down the thermostat rarely fixes it. You end up cooling the whole house to help one room.

A mini-split takes the opposite approach. It cools only the room it's in, with its own temperature control.

Does it work if I don't have ducts?

Yes. One commenter had a hot room and no ductwork at all, and that's not a problem. A mini-split doesn't use your ducts or your existing AC. The indoor and outdoor units connect through a line set that runs through a small hole in the wall.

Will water run down my wall?

This came up a lot, and the thread landed in the right place: it's not normal. A mini-split makes water as it cools, and that water drains outside through a hose. When water does drip from the indoor unit, the usual cause is a clogged drain line or a refrigerant leak that freezes the coil.

The way to prevent it is a drain line that's installed correctly and kept clear. If you ever see dripping or ice, turn the unit off and call a technician.

How do you clean a mini-split?

One commenter summed up what a lot of owners feel:

"Where is the drainage pipe? I had one installed but I have no idea how to access that."

You shouldn't have to guess. Here's the basic routine:

• Every month or two: Clean the filters.
• Once a year: Have a technician do a tune-up. In humid places like Texas, this also keeps the drain line clear.

Ask your installer to show you where the drain line runs before they leave.

What does it cost?

One commenter reported quotes from $4,700 to $8,000 for a single unit, so it's easy to see why people are unsure what to expect. The price depends on the size of the room, the unit and the electrical work.

A typical bedroom with us runs about $1,900 to $4,000, including the unit and a standard install. If you need a new electrical circuit, that adds $300 to $1,200. These are estimates, not quotes. Our estimator gives you a range for your room in a few clicks.

Can I install one myself?

Some people in the thread did, and they were happy with it. It's a real project, though. You need a 240V circuit, room on your electrical panel and a place for the outdoor unit. The refrigerant lines also need to be connected correctly, and the drain has to be set up so water runs where it should.

If you're comfortable with all of that, it's doable. If not, that's where we come in.

When a mini-split won't fix it

This was some of the best advice in the thread:

"If your issue is really lack of insulation or bad drafts, you'd want to fix that problem first."

A mini-split can't make up for a room that's losing air, and it will run harder trying. Other commenters had good luck with window tint on west-facing windows, which can help any room that gets strong afternoon sun.

We'd rather tell you that up front than sell you something that won't solve the problem.

Got a room like this?

If you have a room that never cools down, contact us for a free estimate. We'll look at the room and tell you what makes sense. You can also read more answers on our FAQ page.