Building a new house need advice with HVAC
We are getting ready to build a new home. I would like some advice on HVAC systems. The house is about 3900 sqft. We are building in the Seattle, Washington area, fairly moderate climate. We want to install a energy effecient system that is reliable and will be comfortable. We are not really interested in having air conditioning. Currently our contractor is recommending a hybrid system with a Carrier gas furnace and a Carrier 5 ton puron heat pump. The house will be two stories with about 2,700 sqft on the main floor and 1,300 upstairs. It will have about 350 sqft on the main floor with hydronic heating. Any input would be appreciated. Thanks
I'd be tempted to hire a HVAC design consultant vs. relying on your GC or his HVAC sub to design a system.
There's no better time to do it right then while you're in the planning phase.
I'd also specify metal ductwork. Here on the left coast they seem to love to use Flex.
Try and get someone like this:
Thanks for the advice Dave.
In floor radiant heat loops with a nice boiler and tekmar controls.
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I'm a little confused. What will be your heat source for the hydronic system? It sounds like you'll have a heat pump, furnace and a boiler? Is the heat pump an air to water?
Originally Posted by newhouse11
If you don't care about ac, why bother with a heat pump? Gas furnaces can get pretty high efficiencies. In my opinion, if you want reliability, stay away from heat pumps, unless cooling is a priority along with heating your house. If you decide on a forced air system, tell your installer that you want balancing dampers on all branch lines so each room can get proper air flow. The little dampers on the discharge vents that close with a thumbwheel or lever are not the same and do not do the same as a balancing damper.A pro will give you a heat loss/ heat gain calculation and provide you with the proper heating/cooling CFM required for each room. Once the system is installed the air flow should be measured and balanced at each room and return.
A hydronic system is effecient but don't get that confused with "cheap to operate." Hydronic systems do not have as quick a recovery time as forced air systems so unless you don't care how long it takes to warm your house in the morning, you shouldn't set them back very far at night. They are a comfortable system but the disign is critical, as in all HVAC systems, don't skimp on design.
And on the right coast & anywhere in between. Flex isn't just used in any particular geographical region.
Originally Posted by davefr
Metal is good but so is flex if it's done right. Let's not muddy the waters with confusing info for the HO.
I guess the point I never really made is that metal is much more forgiving to a less then perfect installation then flex.
Originally Posted by Special Ed
Flex is easiliy damaged, has more resistance to air flow and must be installed 100% perfectly. If the wrong tape or mastic is used then it can fall off the junction boxes over time. If the tie wrap tension is not correct or loosens then it can also come off. It also has the be perfectly supported or it'll fall off at the connection points. And all this can occur in very hard to access areas. In addition flex only comes in round. Tin can be formed in just about and shape and that may be an advantage in certain situations.
Maybe my opinion is tainted because I spent 2 miserable days in my crawl space tuning up my flex ducts where I saw first hand all the points of junction leakage. If I had known then what I know now I'd never have let the contractor install this crap.
If I were building a new home any contractor that even mentioned flex would be given the boot. I'd take tin regardless of cost.
The OP can obviously do whatever he wants but this is just one perspective.
Last edited by davefr; 03-01-2007 at 02:02 PM.
I like metal, too, & in a perfect world I would install it a lot more. Unfortunately, most of the homes I look at are older, space is limited & no one seems to be willing to shell out the dough for all new metal ducts. That & there doesn't seem to be any experienced tinbenders here to pre-fab it for me. I'm way small-time so, no, I don't have a dedicated sheetmetal shop. Soooooo, if a HO wants a new duct system they're gonna get flex - done right!
If you dont need AC
If you don’t need AC you should just ruff it in so you could have it in the future also do the vacuum system and alarm system.(Good selling point if you ever move ) I would suggest radiant floor heat in some but not all locations. The bathrooms are a must and have it run in back of the tub the mirror and about a foot up the wall, also have it insulated the best possible way, especially on the outside walls in back of the tub/shower/hot tub Use forced hot water baseboard and lots of zones. I like zone valves and use a circulator with a bypass at the pump just incase you need to switch it over and change the pump. I also like to keep it simple so Burnham with bucket but to each there own. You would need to talk this out with a contractor in you area but that’s a start for this point of view.
Just did a house in Seattle. Home owner stated that the climate is damp not hot. Was unable to handle mold/dust mites because outside moisture. He also wanted fresh air ventilation. Used a whole house ventilating dehumidifier for fresh air and humidity control winter and summer. Hopefully he sees your post and responds.
Originally Posted by newhouse11
If you are not interested in a/c, a gas heater will do. A small heat pump-a/c would be nice as a duel source of heat and a little cooling on the real hot days. The dehu TB
Originally Posted by newhouse11
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