SERVING 
Here in the Atlanta area, we enjoy springtime weather through much of March and April. But as nice as springtime is, these are tricky months when it comes to heating and air conditioning.
On one hand, you don’t need to run your system as much – and that’s good! On the other hand, you don’t want your home to feel stuffy or humid. Should you open your windows? Run the system occasionally to move some air around. Turn the blower fan on?
Such are the complications we experience during the shoulder seasons.
And while it might be easy to beat around the bush and offer platitudes like, “different people are comfortable in different conditions,” or “sure, run the AC if you want some airflow,” there are a few common problems – and common solutions – that can cure almost anybody’s springtime comfort problems.
Enemy, thy name is Humidity.
Hey, it’s 72 degrees outside! Time to open all the windows and let in some fresh air, right?
Well, that depends. 72 degrees might be a comfortable temperature, but other things are going on outside that might not be so comfortable:
- Pollen and other allergens: Opening your windows in springtime exposes you to all the stuff that’s blooming and the human activities intended to curb it. In other words, pollen from plants and dust/dirt from lawnmowers. It’s getting in your house and sticking to your carpet, curtains, walls, and lungs.
- Humidity: This is the big one. You can sneeze the pollen away, vacuum your carpet, and wash your curtains. But humidity collects in your house and stays there. Every time you open your windows, it gets in. High relative humidity (RH) indoors is a breeding ground for dust mites. It’s the main reason you’re still sneezing despite taking that daily Claritin.
One advantage of running the AC in peak summer is that it sucks all the humidity out of your house. During the spring and fall, that’s not happening. You’re barely running the AC or furnace at all. The humidity builds up, and you’re powerless to stop it. Opening windows only accelerates the RH increases (and your misery).
Other things that increase your home’s RH include:
- Air leakage: little gaps and cracks between your home and the outdoors let in lots of humid air. The biggest ones tend to be a the top (attic) and bottom (crawlspace) of the building envelope.
- Running your blower fan: Setting your blower fan to “on” instead of “auto” might seem like a good idea. Better to move some air around even if I’m not running the AC, you reason. But when you run it after the AC has been on (even if the AC only ran for a little while), all you’re doing is blowing air across a wet evaporator coil. And when you do that, a lot of moisture enters your living space.
- Cooking and showering: Kitchen fans and bathroom fans help with this but enjoying a long hot one before cooking spaghetti will always increase the RH of your surrounding environment.
Here in the American South, humidity is a fact of life. When we’re outdoors, there’s nothing we can do about it. But when we’re indoors, humidity is our mortal enemy. Keeping RH below 55% (and preferably below 50%) is necessary to maintain healthy conditions, especially if you suffer from allergies.
How can you get there?
First things first: Cut off humidity sources and monitor your RH
When possible, try to solve comfort problems with home modifications instead of installing new HVAC hardware. We recommend doing the following to lower indoor humidity (in order of priority):
- Seal air leaks. This is how most of the humidity in your home got there. A blower door test and thermal imaging show you all your air leaks, large and small, and help you prioritize air leakage mitigation. We perform these tests as part of our whole-home assessment.
- Trade your blower fan for ceiling fans. Running your blower fan when the heat or AC isn’t on does more harm than good (see above). If you want to circulate air, use ceiling fans instead. Leave the windows closed on humid days.
- Optimize bathroom and kitchen ventilation. Turn on your bath fan before every shower and run it for 10 minutes after you turn off the water. If your kitchen hood just filters air but doesn’t vent to the outside, consider installing a vented kitchen fan that does. Ok, that improvement does involve installing equipment, but only a few modest components.
You might solve your humidity problem with just these improvements. To be sure, you’ll need to buy a humidistat, mount it in a central location inside your home, and keep tabs on RH. Compare how your RH changes after air sealing your attic and crawlspace. Then see if it improves when you add a kitchen fan.
If you’ve done all those things and you’re still having trouble keeping RH below 55%…
Install a whole-house dehumidifier with fresh air ventilation
When you can’t keep humidity at a comfortable level using conventional methods, a dehumidifier is the way to go. In most cases, a whole-house dehumidifier connects to your existing ductwork. It turns on any time your RH exceeds your preset level – usually somewhere in the neighborhood of 50%.
If you have a single-stage air conditioner, the dehumidifier also helps during the balmy summer months. Standard AC systems are usually fine for removing heat but can struggle to remove enough humidity. Dehumidifiers pick up the slack for your air conditioner, helping you stay cool and dry.
Another great thing about dehumidifiers is the option to connect them to fresh air. A small duct branches off from the dehumidifier and pulls in air from the outdoors any time you want to ventilate. The air is filtered inside the dehumidifier – no pollen or allergens enter your living space.
It’s like opening a window, but without the humidity or pollution.
Other cures for springtime discomfort: inspections and incentives
Another thing about spring is that it’s a great time to inspect your HVAC equipment and perform whole-house energy testing. After all, you’re poised to put a lot of stress on your air conditioner starting in late May, so it’s smart to ensure your system works properly before you need it.
If there’s something wrong and you have to go without AC, it’s no biggie. It’s only March, after all. There’s plenty of time to fix it. Spring is a much better time of year to go without AC than, say… July.
Using springtime to identify and prioritize energy use improvements is a good idea, too. Make the improvements now, and you’ll be in good shape for the temperature extremes of peak summer!
Your utility bill won’t be as high as it was last year either.
Speaking of utility bills…
Financial incentives are common in the springtime, too. Your local utility company might offer an energy-saving program or provide rebates for certain home improvements during the spring, so it’s a good idea to see what they’ve got going on this year.
The same goes for HVAC manufacturers, who are keen to sell more systems as the weather heats up. Spring is when they offer a lot of deals and promos.
Spring is beautiful. You deserve to enjoy it.
Get out and soak up the great weather! And when you do have to go inside, rest assured that there are plenty of ways to stay comfortable and save money doing it – even when you’re not running the heat or AC.
By keeping humidity at bay and taking advantage of energy-saving opportunities, you can solve all your springtime heating and air problems. You’ll breathe healthy air inside your home and keep sneezing to a minimum.
Who knows? On the odd day when the pollen count is low and the humidity is below 55%, you might even decide to open a window.
