home improvement ideas?

[Keyboard Ninja]

A friend is buying her first condo in Houston, and she is debating on an electronic thermostat or a dehumidifier for her first "home improvement" purchase. She claims that the electronic thermostat will help cut down the electric bills, but I told her the dehumidifier would probably be my first choice. Humidity sucks and cranking down the A/C doesn't help much in my opinion either. Sure it'll keep things cool, but you'll still feel wet. I'm also thinking with the right dehumidifier her electric bill won't be that bad because she won't need to run her A/C as hard.

So who has either one, and what direction should she go with?

 

[OAG]

IMO 6 of 1 and a half dozen of the other. However, I would purchase and properly program a set back thermostat (I assume she does not have a heat pump as these have issues especially in the winter) as that will conserve and (reduce the electric bill somewhat). It has been my experience that dehumidifiers (and I do have and use one) are not that efficient in getting the humidity out of larger areas. Maybe in her case the Condo is small enough to use one efficiently. There is a bit of a noise problem with them so she should look into one with a quiet motor (if there is such around) and one that has a timer function where it would turn off when she does not want to hear it (at night). If she cannot find one with the timer function she could DIY with a heavy duty stand alone timer (like the ones used for lights - just be sure it will handle the power load of the dehumidifier - do not want any electrical fires).

 

[HFWR]

Seems to me a dehumidifier and A/C are redundant, but I've never lived in Houston, so YMMV.

My next home improvement project involves a kitchen match and charcoal lighter fluid...

 

[REWahoo]

Assuming she doesn't have a heat pump, go with the setback thermostat. A properly working AC system will do a decent job of dehumidifying, no need for a separate unit.

 

[DanDHRT]

She might want to start of with an enegy audit of the condo.

Many local utilities offer them for free. Ours didn't but it was still well worth the $325 we paid.

This way she will have an independent review of the energy efficiency / inefficiencies of the condo before making any $$$ investment in energy saving products.

Personally I'd go with both the dehumidifier (especialy with Houston's high humidity) and the electronic thermostate.

However, the results from the energy audit will guide her on the biggest bang for the buck of energy conservation approaches for her specific condo.

Who knows? The biggest bang for the buck might be caulking around all of the window frames on the outside and inside of the condo? Or exterior solar shades on the outside of the east, south and west facing windows? Or ....

Dan

 

[cute fuzzy bunny]

Air conditioning units dehumidify as part of their process, and they do it quite aggressively. As soon as warm moist air hits the cold a/c coil any moisture in it condenses on the coil, drips off and goes to the condensate drain. Now if the condensate drain is clogged or its an all-in-one unit thats outside and not tipped at the right angle, condensate can collect in the pan and be reintroduced into the air.

Some more efficient air conditioners do try to limit the reduction of humidity to improve efficiency, since that moisture saps cold from the coil and then runs off into the ground as cold water. In fact, there are some new air conditioning technologies coming out in a year or two specifically targeted towards the pacific southwest that dont do very much dehumidification at all since the air is already dry. Those are expected to be 20% or more efficient that current a/c technology.

Dehumidifiers are essentially very inefficient air conditioners. They shoot to remove as much water as possible. So an average dehumidifier will take more energy than an air conditioner to remove the same amount of humidity. As a double whammy, they produce quite a bit of heat and blow it back into the house, which your air conditioner then has to work to remove. To get an idea of this, the next time you see a window air conditioner running inside a store, put your hand around the back and feel the blast of 120 degree hot air coming out of it.

The electronic thermostat will only save money to the extent that she can program it to automatically drop and raise the temperature of the condo during the night and during the days she's at work. Depending on where this is, how much temp change she feels comfortable with at night, and how much she works, she could save 10-20% on her heating and cooling bills. Or almost nothing at all. She could accomplish the same thing by pushing the buttons on the thermo when she leaves, returns home, goes to bed, and wakes up. Free. See what sort of results she gets.

Get a humidistat and see what the average humidity in the condo is. If its over 50% then something should be done about it. Either the air conditioner needs to run more, you'll need a new one that allows a humidistat and has cycles to run longer to remove more humidity, or you'll need a dehumidifier to reduce the moisture...but the electric bill is going to go UP in that last option, not down.

 

[Leonidas]

The bunny got it right I think.

I have a dehumidifier I bought a couple of years back, but programmable thermostats were the very first change I made after buying my house twenty years ago. I think the best investment your friend can make would be to first make sure that her place is energy efficient.

That said, the reason I have a dehumidifier is primarily to combat dust mites. The little buggers like humidity and usually die off when it's lowered. I run it during periods of high humidity to discourage dust mites because they contribute greatly to allergies. And allergies are an issue in Houston. I find when I keep the humidity from getting too high that it cuts down on coughing, sneezing, etc.

The dehumidifier does make me feel more comfortable if I use it during high humidity, but it puts out so much heat that it will make a room unpleasantly warm. When I use it, I will run it in rooms that nobody is using at the moment because trying to stay there while it's running is a miserable experience.

 

[cute fuzzy bunny]

Dust mites do like humidity, and one of their primary foods is mold spores. Another is dried skin flakes, so dont turn the humidity down too low.

Generally 40-45% is comfortable, not too dry, not too wet, doesnt encourage mold growth, and retards dust mites.

BTW, a good way to do a quick dehumidification is to let the temps in the house get up to 82-84, then turn the a/c down to 70 and let it run until the humidity slips below 45. Then turn it off a while to let the condensate pan fully drain and dry. Then run it again for another long cycle until you get about 40%.

Some newer, more expensive a/c units let you set a cooling humidity level and they'll do all sorts of fancy tricks to get the humidity down automatically. Ours will run the temp a degree or two lower than the set point to continue a cooling/dehumidification cycle and will also cycle on and off to allow the condensate pan to drain.

Best bet is to not build any up in the first place. One of your biggest sources of humidity is not running the bathroom vent fan when you're taking a shower. A lot of people like the "hot and steamy" bathroom, especially on a cold morning. Unfortunately that hot and steamy bathroom will add about 10% humidity to your house. Another big source if you cook a lot is moisture from a gas burner and from foods or boiling water. Use the vent hood on low to disperse that.

As a testament to the heat coming from a dehumidifier, I used to put ours in front of the air return grill for the central air. When it wasnt on, we'd get a 20 degree drop in inlet to outlet temperature. With it on, the difference was 1-2 degrees.

We lived in a tough area though. It was mostly farming, largely peaches, and the farmers would flood the fields every night from their well pumps. Water was 6-12" deep for thousands and thousands of acres all around us. The ground was pretty well saturated and the concrete slab would wick it up. When we swapped the carpet I sealed the concrete and laid down a vapor barrier. That really cut it down.

 

[FIREd]

I live in humid AL and my A/C system does a fine job of dehumidifying the house. Currently only 42% humidity in the house in the midst of a muggy summer and after torrential rains from Fay. So I'd go with the thermostat. By the way if she has a heat pump, she has to make sure she buys a compatible thermostat.

 

[Sam]

She might want to start of with an enegy audit of the condo.

Many local utilities offer them for free. Ours didn't but it was still well worth the $325 we paid.

Dan

I'm curious. What exactly does an energy audit do? $325 sounds a little too steep for me.

 

[honobob]

I'm curious. What exactly does an energy audit do? $325 sounds a little too steep for me.

I hoping it at least included a couple of those thermograph pictures that shows green good and red, OMG, you're heating the whole neighborhood!!
Otherwise, $325 seems way too high.

Some senior services also provide this audit and will even provide no cost/low cost solutions.

 

[Keyboard Ninja]

Thanks for the ideas!! How would someone know if they had a heatpump besides asking? Is there some sort of special feature on the existing thermostat that would tip her off?

 

[REWahoo]

How would someone know if they had a heatpump besides asking? Is there some sort of special feature on the existing thermostat that would tip her off?

Maybe.

If the thermostat has an indicator light labeled "emergency heat" or "aux heat", then it is a heat pump. That system kicks in when the temp gets too low for the heat pump to sufficiently warm the air. See this for more information on how a heat pump works.

 

[OAG]

There are a few ways - like how it acts. But the best way IMO is to read the plates attached to the unit(s) - Outside unit and inside unit. Also by taking the make and model number from the plates you could also go to the manufacturer's site. However, it should be apparent from reading the plates. While you are there look for the SEER - and the age of the unit - a low SEER (below 10) and/or an age over 10 years would indicate a very good candidate for replacement (add a Humidity and good Air Cleaner to the unit at the same time). Kind of a tough expense after just buying the Condo but if she plans to stay for a good while it will pay for itself over time.

 

[TromboneAl]

Are you guys missing the fact that a setback thermostat only costs about $40?

 

[REWahoo]

Are you guys missing the fact that a setback thermostat only costs about $40?

Not really. I've never been a fan of using them for heat pumps - at least not for heating. Even though the newer and more sophisticated setback thermostats can regulate the warm-up phase to limit the possibility of the aux heat strip coming on (inefficient and uses lots of electricity), the warm up phase can be very long on nights with the temps in the 30's and low 40's. Not much savings as I see it.