Energy effeciency of new home

[teddy bear]

No, we have spent over a year checking out builders and found one who is highly praised. I have seen a number of his new construction houses and I dont have any concerns with the tighness of the house. Especially around the windows.

I was refering to the fact as houses are built tigher, the amount of fresh air infiltrating the declines to the point were most IAQ experts suggest fresh air ventilation be mechanically controlled. Many of the poster on this forum do not support mechanical fresh air ventilation. I do. In addition, green grass climates have enough wet cool weather that well insulated homes do not have enough cooling load to remove the moisture of the occupants and fresh air to maintain <50RH. Regards TB

[beenthere]

its not that we don't support mechanical ventilation. Just don't push it when it is not needed.

A 2000 sq ft house with 4 occupants needs more fresh air, then a 3500 sq ft house with only 2 occupants.

So the larger house may be tighter, and still not need mechanical ventilation.

Should he allow provisions for it, sure.

But if he needs 5 to 6 tons for it, its not all that tight.

[gonefishin]

I was refering to the fact as houses are built tigher, the amount of fresh air infiltrating the declines to the point were most IAQ experts suggest fresh air ventilation be mechanically controlled. Many of the poster on this forum do not support mechanical fresh air ventilation. I do. In addition, green grass climates have enough wet cool weather that well insulated homes do not have enough cooling load to remove the moisture of the occupants and fresh air to maintain <50RH. Regards TB

I made another post today. I am interested in the ICF reward wall system. The people I spoke with today use this and they do use a heat/air exchanger near the furnace to circulate outside air. I would not have a problem with this either. I just do not know enough about this. What do you mean a cooling load to remove moisture?

thanks again

[hangfirew8]

What do you mean a cooling load to remove moisture?

If the A/C doesn't have to run much to cool the house, it won't dehumidify much.

Typical problem in humid areas in Spring.

-HF

[energy_rater_La]

have you checked into SIPS building?
IMO this is by far the more superior building system.
SIPS panels are osb on both sides with foam sandwiched between.
No thermal loss due to framing members for a continous R-value.
Stick framed homes have 20 to 30&#37; of walls that are wood only
depending on framing methods. SIPS eliminates these areas where
studs lessen overall wall insulation.
SIPS panels for walls, floors, ceiling or roof installs are available, in
both 4" and 6" thickness.

I've tested (blower door tests)on many of these homes (sips, icf, stick built) and find SIPS to be the 'tighter' of the three.
In a 'tighter' house hvac load is reduced. I think that ICF has a hvac sizing and that SIPS also advocates proper sizing of system.
The savings of smaller properly sized hvac system will allow you to spend that $$
on other efficiency choices.

If your home is 'tight' meaning that the air changes per hour are less than .25 ach
you will need to add make up air. Otherwise your home will have the potential for many
IAQ issues, along with health issues.

Many people do not understand the need for fresh air because the homes & the ductwork are not tested for leakage. A home that has a lot of air infiltration will
not need fresh air, because the house will suck air in through the many leakage areas.
Once these leakage areas are sealed, then adding fresh air allows you to filter, and dehumidify the air before it enters the home.

I hear a lot of folks saying that their house is tight..but the fact is that you don't know
until it is tested.
Also in my area I find lots of duct leakage. In new construction
1.5 to 2 tons of leakage is not uncommon. With proper sealing methods duct leakage can be reduced to 10%. Companies like Comfort Institute promote 'the house as a system' which incorperates all the componets working together.

Many of the hvac companies that I work with had never tested their ductwork.
For them to understand the testing methods and find the areas of leakage made
it much easier to achieve lesser duct leakage amounts.

Also if you can locate your ductwork in the conditoned space leakage becomes a non issue, and is a great savings.
(anyone ever play around with Man J and customize the inputs to include ducts in conditoned space??)

I like Jeldwen windows..mostly because it is an affordable window that is well made
..and of course it tests well. Do invest in the low e.


Best of luck to you and congrats on building better.

[teddy bear]

I made another post today. I am interested in the ICF reward wall system. The people I spoke with today use this and they do use a heat/air exchanger near the furnace to circulate outside air. I would not have a problem with this either. I just do not know enough about this. What do you mean a cooling load to remove moisture?

thanks again

Just did another post explaining the concept. I have a well insulated home that has required very little a/c so far this year dispite many 85^F days. I remove 30-50 pints of water each day to maintain <50%RH. I did not start my dehumidifier until my basement was+70%RH and the mainfloor was +60%RH. That waas about 3 weeks ago. Find my previous post with data graphs. Today Madison ws 85^F, 65%RH, my house is 76^F, 50%RH with very little a/c. I will post the data next week. MY flaw is that I do not provide mechanical fresh air, only a cracked window plus building imperfections. A cracked window is not enough fresh air when the home is occupied. I will correct soon. Regards TB

[gonefishin]

[QUOTE=energy_rater_La;1923068]have you checked into SIPS building?
IMO this is by far the more superior building system.
SIPS panels are osb on both sides with foam sandwiched between.
No thermal loss due to framing members for a continous R-value.
Stick framed homes have 20 to 30% of walls that are wood only
depending on framing methods. SIPS eliminates these areas where
studs lessen overall wall insulation.
SIPS panels for walls, floors, ceiling or roof installs are available, in
both 4" and 6" thickness.



I have checked into SIPS building materials. IF it does what is says, it looks very impressive. However, this would not be a good fit for us what we are doing currently. I cannot bring in a totally new construction method and not step on my builders toes. The ICF is a little different. I Like the fact that these ways of building are far superior to what is done traditionally and I am willing to change my way of thinking, I just have to help my builder do the same.
thanks for the comments.

[paul42]

WE are building a 3500 sq foot home in Ohio. Front door faces east Back door faces West and sits on a hill.

I have been talking to reps from Low-E to find ways to lower our utility bills when this project is complete.

We are going with a 6ton WF geothermal.

I wanted to know what you thought of these fairly new products:

1.) Slabshield- polyethylene foam with aluminum: placed under the basement before cement is poured. This provides an R value of R3
Simple to install and replaces the mil vapor barrier. Cost is mid 40cents per foot.

2) Low E- House wrap. Aluminum coated W/ closed cell polyethylene. Blocks 97% radiant energy. Provides Rvalue of R4. Cost is about double that of Tyvek house wrap.

3) Micro E- for attics/roof: Aluminum facing 1/8" thick. Placed between joists, easy to install stapled with tabs. Rep. claims this will reduce the temperature of the attic between 30- 40 degrees! Cost is close to the house wrap.


If these work, they sound like they could be very beneficial in the long run. The initial cost (I am guessing) may be around 4-5,000 to install all of these. Which seems low to me for improvement on effeciency. They may produce good returns by lower heating/cooling costs over the next many years.

Have any of you used/installed these products? Does is seem to be worth the initial expense?

thanks

No two houses are the same, everything changes with climate, house layout, how a house is orientated, the owner's expectations, etc...

But, I have 4,000 sq. ft. of conditioned space in north central Texas, I keep my house at 74 degrees and 42% humidity, and it all works with a 2 ton heat pump. It is all done with a fairly standard frame construction.

Energy efficiency (for my climate) depends on
1. Put the duct work in conditioned space
2. Make sure the sun never shines in a window in the summer time
3. Control Infiltration - windows and doors are not the primary cause of leaky houses
4. More than minimum standards for insulation. (the least important of them all)

Get all of that RIGHT, and the HVAC part is easy.