Page 1 of 2 12 LastLast
Results 1 to 13 of 19
  1. #1
    Join Date
    Jan 2007
    Posts
    29

    Bonus room - new construction

    I'm building a new home, 1850 sq ft downstairs with a 350 sq ft bonus room above the garage.

    I'm getting ALL kinds of different advice about how to cool it. From a 1 system 5 ton to a two system with 3.5 (downstairs) and 1.5 ton (bonus room).

    I'm also hearing that a minisplit ductless system (9000 btu) for the bonus room would be the best option....and a 3.5 ton central system for downstairs.

    Any opinions here on what will be the best option?

  2. #2
    Join Date
    Mar 2003
    Location
    PA/DE area
    Posts
    1,535
    In our area the MINIS do not have enough back up heat to cover the load on COLD days,why not a zone system??
    It's NOT the BRAND,it's the company that installs it!!!!!

  3. #3
    Join Date
    Jan 2007
    Posts
    29
    Quote Originally Posted by heatpumpguru View Post
    In our area the MINIS do not have enough back up heat to cover the load on COLD days,why not a zone system??
    My current thinking is that maybe a zone system is OK if you plan to use the bonus room daily. Otherwise I may be using too big of a unit to cool the lower part of the house when I'm not using the bonus room. For example in a couple of years my kids will be in college and it will just be me and the wife. I doubt that we use the room near as much then.

    I'm starting to lean toward a 3.5 central system downstairs and a 1.5 central system upstairs and just forget about it.

    Unless someone just swears by the mini ductless as a better option for the bonus room than the 1.5 ton duct system?

  4. #4
    Join Date
    Jan 2003
    Posts
    243
    minisplits are best used when there is no room for duct. Its hard to say without looking at the house, but I would think that the 2 systems would be best. Judging by your name, I presume that you are from Arkansas which means that heatpumps work great in your area. I recommend a heatpump.

  5. #5
    Join Date
    Dec 2006
    Location
    Dallas
    Posts
    189
    Be sure the contractor performs thermal load calculations for the bonus room and the house. You are probably not heating/cooling the garage below the bonus room, so be sure to insulate the floor.

    If you insulated the bonus room at R14 in all 6 directions with a few windows, 30% duct loss (attic temp and leaks) you could be as low as .5 tons cooling for that one room. Get stingy on insulation & window efficiency and you could be at 1 ton real fast. If you are using insulation, I am quite certain 1.5 tons for that room would be big overkill.

    About a month ago I posted a similar zoning preference question for a two story home. I asked about the PRO's and CONS of 2 units Vs 1 larger unit. In my opinion the collective recommendation was zone with one large unit if you can afford it up front. One large unit means one less unit to purchase, install and service.

    Get quotes and ask for themal loads to be calculated using the materials used for your construction.

    Zoning and programmable thermostats are great. My household is two humans one dog in 3500 sq ft, Dec 15 to Jan 15 gas bill in Dallas was $120.

  6. #6
    Join Date
    May 2000
    Location
    Michigan
    Posts
    125
    first of all, a load calc will tell you what you need for equipment in the new house. secondly, zone it!
    scenario...you get home late one night. walk into the dark house from the garage and hit the light switch. what happens? do all of the lights in the house come on? NO, i hope not. your lighting is zoned. why not heating and cooling too? heat/cool what you want and when you want it, at the temperature you desire. maximize comfort and efficiency. zoning makes for a very comfortable house. and you can do it with less equipment meaning less maintenance down the road.

  7. #7
    Join Date
    Jan 2007
    Posts
    29
    Quote Originally Posted by dwiz View Post
    first of all, a load calc will tell you what you need for equipment in the new house. secondly, zone it!
    scenario...you get home late one night. walk into the dark house from the garage and hit the light switch. what happens? do all of the lights in the house come on? NO, i hope not. your lighting is zoned. why not heating and cooling too? heat/cool what you want and when you want it, at the temperature you desire. maximize comfort and efficiency. zoning makes for a very comfortable house. and you can do it with less equipment meaning less maintenance down the road.
    The load calculator says I need 4.5 tons. Two contractors say I should go with a 5 ton, one says a 4 ton is all I need. Is it better to be too high or too low....especially if I zone it?

    Also, I can see keeping the thermostat in the bonus room way down when we're not using it...which I expect will only be on the weekends. How does this impact the size of the unit I need?

    Is it recommended to zone every room with it's own thermostat or just zone the upper and lower levels?

  8. #8
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    34,095
    So they really did a heat gain calc? 3.5 tons for 1800 sq ft of new construction just seems high to me unless you have a lot of windows or are light on insulation. 5 tons for 2300 sq ft likewise seems big. Be sure they do things right and preferably use 2 stage equipment or you could have some short cycling trying to make a 5 ton unit push air into a small room. If I were doing it, I'd go the 2 systems.

    Zoning every room isn't practical, zoning by floor is better. Again, has to be done right. We see too many that aren't

  9. #9
    Join Date
    Jan 2007
    Posts
    29
    I do have a LOT of big windows as well as 9 and 12 foot ceilings and this is the south so it gets really hot in the summer. I'm using low E windows and fully insulating everything. The guy that did the most extensive calculations recommended 3.5 downstairs and 1.5 ton upstairs above the garage as the best option over a single 5 ton system. I suppose this is probably the safest bet.

    However the 4 ton zoned option for the bonus room was about $2000 less. I would sure rather do this if I knew it would work well. Just wish I freakin knew!

  10. #10
    Join Date
    Jan 2007
    Posts
    29
    Quote Originally Posted by BaldLoonie View Post
    Be sure they do things right and preferably use 2 stage equipment or you could have some short cycling trying to make a 5 ton unit push air into a small room. (
    BTW, what do u mean by "2 stage equipment"?

  11. #11
    Join Date
    Mar 2003
    Location
    PA/DE area
    Posts
    1,535
    Put in 2 stage, zoned equipment and you cannot go wrong!!!You also have less compressors and you can only FIRE the tonnage that is needed because you are never in evry zone at the same time calling for HVAC>
    It's NOT the BRAND,it's the company that installs it!!!!!

  12. #12
    Join Date
    Jan 2007
    Posts
    29
    Quote Originally Posted by heatpumpguru View Post
    Put in 2 stage, zoned equipment and you cannot go wrong!!!You also have less compressors and you can only FIRE the tonnage that is needed because you are never in evry zone at the same time calling for HVAC>
    So I could get by with a 4 ton instead of a 5 ton?

  13. #13
    Join Date
    Mar 2003
    Location
    PA/DE area
    Posts
    1,535
    Maybe the load will tell,but the zoning does help control the load and I think most on site would agree with zone system if it is close the would say go with 4 VS 5 ton system. Also duct work is key with zone system. I do not care what you put in 4 ton or 5 ton,if the ducts suck, it sucks!! SEER is nice but the heart of a GREAT system is the ductwork!!
    It's NOT the BRAND,it's the company that installs it!!!!!

Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event