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danxp 06-13-2012 12:26 PM

New Heating & AC
 
i'm doing a full gut renovation of my house and will be replacing all existing equipment/ductwork with brand new... it'll essentially be like a new construction build... wanted to get some feedback from the gurus here...

- house will be ~2300sf 4br/3ba/2car garage
- spray foam closed cell insulation
- 2 zones (1st and 2nd floor)
- low-e andersen 400series windows throughout
- baseboard heating
- will have no chimney so i'm doing hi-efficiency boiler and tankless water heater so i could direct-vent (any advice on which boiler to get?)
- some calculations call for anywhere from a 90k-110k btu boiler... whom to believe?
- getting a 4ton 80% unit to install in the attic
- all new ductwork
- boiler in the unfinished basement
- thinking of one of those boiler/water heater combos but am afraid the gpm will not be sufficient

still in the planning phase so i'm open to changes/suggestions on ways to do things better/cheaper (placing the emphasis on value)

oh and i'm also thinking about foregoing the baseboard heating and making a forced/warm air setup if it's worth it...

thanks all.

Marty S. 06-13-2012 12:37 PM

4 ton is likely double what you need with closed cell foam

beenthere 06-13-2012 01:23 PM

Closed cell insulation, shou mean that the boiler and A/ size you posted are twice as big as you need. Also, you will probably need mechanical ventilation.

Have a proper heat load calc done. To find out the proper size. May be able to use a 45,000 or 50,000 BTU hot air furnace for heat, and a 2 ton A/C.

danxp 06-13-2012 03:24 PM

wow... closed cell makes that much of a difference? my exterior walls are 2x4 so i'll have about 3 inches in there at an r-value of 6 or 7 per inch which means i'll get r18-r21 in my exterior walls...

so a 2ton unit in the attic and a 50k btu boiler in the basement?

any good brand recommendations? or any brands i should stay away from?

i'm looking to order from either pexsupply.com or ecomfort.com...

thanks all.

REP 06-13-2012 03:56 PM

OK things like this just upset me.Making wild claims about size just to sound important without telling you how to find out exactly what you need is stupid.
You need to have a manual "J" and AND a manual "D" done to find out exactly what your house needs..
If you are concerned about GOM then get a Indirect water heater.You will be very satisfied with it.Stay away from a tankless.
Investigate infloor for your heating.It is the most comfortable from of heating.
As far as equipment goes,find a good contractor with maybe a NATE rating and go with his reccomandations.
This is not the time to be conservative.Anything installed now you will have to live with for the next 20 years or more.

danxp 06-13-2012 04:21 PM

Quote:

Originally Posted by REP (Post 942684)
OK things like this just upset me.Making wild claims about size just to sound important without telling you how to find out exactly what you need is stupid.
You need to have a manual "J" and AND a manual "D" done to find out exactly what your house needs..
If you are concerned about GOM then get a Indirect water heater.You will be very satisfied with it.Stay away from a tankless.
Investigate infloor for your heating.It is the most comfortable from of heating.
As far as equipment goes,find a good contractor with maybe a NATE rating and go with his reccomandations.
This is not the time to be conservative.Anything installed now you will have to live with for the next 20 years or more.

i'm confused... what are you saying? what's manual J and D? and what's a GOM?

infloor is gonna be too expensive... i have to go tankless since i'm not going with a chimney and space is at a premium.

beenthere 06-13-2012 05:45 PM

Quote:

Originally Posted by REP (Post 942684)
You need to have a manual "J" and AND a manual "D" done to find out exactly what your house needs..

It should be a Manual J version 8(in the USA, Canada has its own load calc program), as that version has better numbers for doing homes that are spray foamed.

REP 06-13-2012 09:29 PM

Fat fingers strike again I meant GPM.
If you get a boiler which is what you said you wanted,that needs to be vented.An indirect water heater has no heating on its own and uses the boiler for the heat for domestic hot water.
With a tankless water heater you have to be conceerned with GPM .You don't have trhat problem with an indirect heater.
With a normal boiler,you have to be careful where you put your furniture and be carefull with curtains covering the radiation and you heat the whole cubic footage of the house.With infloor you heat the first five feet from the floor and not the ceiling area.
With normal baseboard you heat the water to 180 degrees.With in floor you heat the floor with 90 degree water.Its a lot cheaper to run the boiler to lower temps.The saving can be very noticible.
Like I said whatever you do you will live with it for the next 20 years.

Missouri Bound 06-13-2012 09:37 PM

The experts are correct about sizing the unit properly. Information on how to do that accurately is here.....ACME:yes:

carmon 06-13-2012 09:39 PM

manual J hhhmmmmmm:eek:

Missouri Bound 06-13-2012 09:53 PM

My first house was baseboard heat with gas fired boiler. Absolutely wonderful. I would do it again if I was building, but I too would use radiant for most of the home, with an additional zone for the garage. But here in MO air conditioning is way more important than heating.

danxp 06-14-2012 01:20 AM

so how much more is in-floor heating as opposed to baseboard?

my plumber is charging me about $12k installed including the hi-efficiency boiler...


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