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hru (heat recovery unit) attached to hvac

Posted by Jagster (My Page) on
Tue, Dec 13, 11 at 11:53

I'm in need of installing a new HVAC and water heater and I was thinking of installing a HRU at the same time. I've researched a bit on the web but some of the info is a little old and I've read some people say that with the newer R410 high SEER units, that they don't create enough hot gasses on the return line to make the HRU work effectively but the HRU rep I spoke with said that they all generate a temperature of around 160 degrees on a 90 degree day (we hit high 90's to over 100 on a regular basis in North Florida). I've also heard that cooling the returning refrigerant can possibly cause problems because the heat pump expects a certain temperature coming back to work right. I'm not familiar enough with HVAC to know what is real and what is myth when it comes to these claims but it seems to me that there has to be a good way to make the best use of heat being pulled out of our houses instead of just warming outside air. The air handler and the water heater are basically right next to each other in the garage.

My house is 3000 sq ft. single story requiring a 5-ton HVAC system and I'm deciding between a 17 SEER and a 15 SEER. Some people have told me that it's very difficult to actually get above 16 SEER with a house this size and the price difference between 15 and 17 is pretty big. I'm leaning towards a 15 SEER if I can also utilize an HRU.

Does anyone here have thoughts, experience, or advice to share on this matter?


Follow-Up Postings:

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RE: hru (heat recovery unit) attached to hvac

I am guessing here but if this were such a great idea wouldn't all the major manufacturers be offering this as an add-on option?

SR


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RE: hru (heat recovery unit) attached to hvac

The theory is awesome and yes it does work but works the best with older 13 and below seer units. Some systems work well with HRU's and some not so well or not at all. I really wanted to go this route and researched and talked with a few hvac pro's that had issues like the unit would operate fine if it was 90 degrees or higher outside but if it was 80 the pressures were too low and the a/c unit wouldn't operate correctly.

Its like Fsq4cw said. The system needs to be designed for it otherwise its anyone's guess how things will work.

If everything works together they are pretty awesome. If not they can cause a huge headache trying to iron out the kinks.

One other idea I brainstormed was using a HRU and a small ground loop or pit with a pump and make a hybrid geothermal/air unit. I doubt it would work though.


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