Return to the Heating & Air Conditioning Forum | Post a Follow-Up

What would you do? (How many units?)

Posted by stumpystump (My Page) on
Mon, Sep 1, 14 at 4:42

We are in the planning stages of building a house. It will be a one story around 2600 to 2800 sq ft.
The builder suggested two two units -- one for the master wing and the other for the rest of the house.
Do we really need two units?

The builder suggested it so we could program the rest of the house at night and not have to cool the other rooms as much while we are sleeping. (We are in central Florida and we like it cool!)

I am researching zones and whatnot but I really don't know much because I have always just had one unit for an entire house or two units (one for upstairs and one for downstairs) So, I would love some expert advice.

Thanks in advance!

Follow-Up Postings:

RE: What would you do? (How many units?)

No you don't need two units but if my home, I would strongly recommend zoning controls to separate your home into several zones served by one quality HVAC system.

The best totally integrated system would be Evolution/Infinity HVAC/zoning controls.

That would be Carrier and Bryant.


This post was edited by tigerdunes on Mon, Sep 1, 14 at 6:03

RE: What would you do? (How many units?)

Many HVAC contractors don't know how to properly install a system with zoning. They try install a single speed furnace or air handler an expect it to work well when only one zone calls for heating or cooling. The two separate systems eliminates some of those problems.

Builders will usually hire the lowest cost HVAC contractor so maybe your builder knows the guy he wants to use may not have the expertise to do a good zoning installation. On the other hand most builders know very little about HVAC so maybe he does not how zoning can work in your house.

There is no reason why a properly installed zoning system cannot be designed for new construction. Meet with the HVAC contractor and talk to him about it.

I suggest all the bedrooms be tied into the same zone. Your house may be big enough to support three zones.

RE: What would you do? (How many units?)

Thanks for the info. I didn't even know about zoning until the other day.
In our floor plans we are trying to find a place for the second unit and that got me thinking about there had to be a better way.

I will ask the builder when we get our new plans and see what is on there.

Because I am pretty clueless (sorry!) about HVAC … you think think I should have one unit, maybe three zones. Any other info I should have before I ask? Tonage, SEER level, anything?
Florida is all about humidity and heat … so I really do want something that will keep me cool year round. I am not one that opens windows and calls it a day. Too hot for that.

RE: What would you do? (How many units?)

The size needs to be determined by a heating and cooling load calculation. The contractor uses the dimensions of the rooms, windows, and insulation values and enters into a software program to determine how many BTUs per hour are needed to heat and cool the house. The equipment is then selected based on this calculation.

The minimum SEER rating by federal law is 13. The best value is usually in the 15-16 SEER range, but it varies by equipment manufacturer. Don't select equipment solely on SEER ratings.

RE: What would you do? (How many units?)

I don't know the "central FL" climate, but if it is anything like South LA, What you need most is a system to not so much keep you cool, but to control humidity. The latter is more difficult to achieve. If you have good humidity control, you can be comfortable at a higher temp. If humidity is high, you won't be comfortable at any temperature. If HVAC design and construction are bad, you will have high humidity.

Your ducts should be inside the house envelope, neither in a vented attic nor in the crawlspace. Consider hiring an energy rater to oversee the planning and construction process. You should have performance criteria for house envelope and duct leakage.

 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!

Return to the Heating & Air Conditioning Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Please review our Rules of Play before posting.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.

Learn more about in-text links on this page here