Fixing a noisy water-source heat pump

January 18, 2012

Q. I live in a condo that is heated and cooled by a water-source, electric heat pump. From what I understand, it’s an unusual system for a residential building. There is no outdoor space or even a balcony, so the unit is inside the apartment in a utility closet. The unit, probably the condenser, is extremely noisy. In a small space like my condominium, it’s similar to the constant noise on a jet airplane. Is there anything that can be done about the noise? With all the condo construction that took place during the housing boom, this must be a fairly common problem.

Arlington

A. Actually, the main working parts of a water-source heat pump are typically located indoors, often in a closet. The more common air-source heat pump is always outside because it extracts or collects heat from outside air. But with a water-source heat pump, the exchange takes place in a system that recirculates water.

Typically, there is a cooling tower, perhaps a water tank on the roof, plus piping to carry the water to and from individual heat pumps. As with other heat pumps, water-source types are considered to be an energy-efficient, practical option.

However, if your unit roars like a jet engine, something is clearly not right. Tom Whiteley, a sales engineer for Havtech, a company in Columbia that sells water-source heat pumps, says noise problems usually result from ducts that are too small. Heat pumps of all types require more airflow than conventional heating and air-conditioning systems, so the contractor might have sized the ducts as he or she had been doing for years, without factoring in the effects of switching to a heat pump.

“If the ductwork is not sized properly, it creates a whole lot of static pressure,” Whiteley said. “Air is trying to get out the sides, and the velocity is higher than it should be.” Typically, ducts should be sized to allow airflow of 1,000 cubic feet per minute, he said, but he’s seen noisy systems where the reading was as high as 1,800 cfm.

So what’s the remedy, short of ripping into the walls to redo the ducts? Whiteley said it might be possible to install an insulated plenum box, a large piece of ductwork that knocks down air velocity.

First step: Call a residential heating and air-conditioning contractor and ask to have your system evaluated.

I was so happy to read your suggestions for how to preserve old wallpaper that has become loosened at the seams. I am trying to preserve the wallpaper in my dining room, but the seams have curled away from the wall in places. I applied seam adhesive, as you suggested, but the paper still curls away and the adhesive can’t do its work. How do I fix this?

Gaithersburg

The earlier question concerned grass cloth, which can easily be damaged by exposure to water. Assuming you don’t have that type of wallcovering, try dampening the seam area first by pressing a damp sponge against it. Once the moisture makes the wallpaper pliable, lift the loose edge with a putty knife just enough so you can squirt a decent amount of seam adhesive underneath. You need more than a drop or two, but not so much that it runs down the face of the wallpaper.

Once the adhesive is in, press the seam down. Wait for the time that the adhesive label recommends (often about 15 minutes) then roll over the area with a wallpaper seam roller. Don’t press too hard or roll over an area numerous times or you’ll squeeze out too much of the adhesive — the same problem that probably occurred when the wallpaper was installed, causing the seams to lift later. Finish by blotting off any adhesive that does get on the front.

The Checklist Read Jeanne Huber’s roundup of home-improvement tasks you should tackle in January at washingtonpost.com/home.

Have a problem in your home?

Send questions to localliving@washpost.com . Put “How To” in the subject line, tell us where you live and try to include a photo.

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