Posted By Nick_M on 01 Mar 2012 11:32 PM
Here is the reality on energy efficiency and resale value of a home that is not new (i.e., >10years old). Home buyers don't care! In 15 years when we sell the house, no one will ask what insulation is between my walls or the U value of my windows. They will want to know if the layout, size and what's in the house is to their liking. I know this because my wife is a Realtor and this is what people want to know. She has never had anyone ask her about insulation type or R value and how the home was air sealed or U value of windows and most homeownerse would proably not even know those answers. Thus, for me and most people building a home on a budget, it truly does come down to ROI with a small level of deviation for comfort.

You nailed it.

95% of home buyers don't care or ask about what's in the walls or ceilings. While some builders are throwing around the green energy builds, they are just sales pitches. The home might have CFLs, low energy use appliances, water saving toilets, etc. but that is about it. They will have typical R-13 (2x4) and R-19 (2x6) fiberglass batts in the walls with R-35 in the attic.

95% of it is about "eye candy". The square footage, the layout of the home, the kitchen finishes and the aesthetics matter.

Posted By Nick_M on 01 Mar 2012 11:32 PM


Sorry to change topics a bit but, ironically, we have another important decision to make that hits ROI vs comfort issue again. The energy consultant is saying that we either need a bath fan to run continuously at 80cfm or I need to add a HRV or ERV in order to get more fresh air in the house. My guess is that I will never see the ROI on the HRV/ERV in 10-15 years living there in comparison to continuous run bath fan. But then I have to weigh the comfort of having a bath fan run continuously, even if it is a super quiet one. Feel free to chime in on this one.

Who says you have to continuously run the bath fan? Just disconnect it after inspection or put it on a ON/OFF switch after inspection.

Your home is a wood home, correct? Why would one need a HRV/ERV unless you sealed it tight with spray foam insulation? Wood homes usually leak enough air that they don't require a HRV. 

Within 15 years there's a real good chance homes will have performance sheets as a requirement to sell a house. Once buyers can look at that, your upgrades will be worth more than you paid. It's a bit of a gamble, but really a safe bet if you look at the past 10 years.

"You nailed it. 95% of home buyers don't care or ask about what's in the walls or ceilings"
Have you bought a General Motors Hummer lately? Isn't that why Detroit said they would continue building SUVs in 2007? Because buyers didn't care about gas mileage? Remember what happened to them?

I totally agree that way too many builders and buyers get caught up in expensive technologies and "green" gimmicks; doesn't mean we all have to. There are smart ways to build houses that will last, that will be inexpensive to heat and that will be totally comfortable, for only a modest cost increase. Your choice.

Posted By Lbear on 02 Mar 2012 12:10 AM

Posted By Nick_M on 01 Mar 2012 11:32 PM


Sorry to change topics a bit but, ironically, we have another important decision to make that hits ROI vs comfort issue again. The energy consultant is saying that we either need a bath fan to run continuously at 80cfm or I need to add a HRV or ERV in order to get more fresh air in the house. My guess is that I will never see the ROI on the HRV/ERV in 10-15 years living there in comparison to continuous run bath fan. But then I have to weigh the comfort of having a bath fan run continuously, even if it is a super quiet one. Feel free to chime in on this one.

Who says you have to continuously run the bath fan? Just disconnect it after inspection or put it on a ON/OFF switch after inspection.

Your home is a wood home, correct? Why would one need a HRV/ERV unless you sealed it tight with spray foam insulation? Wood homes usually leak enough air that they don't require a HRV. 

Nick, its not a ROI vs comfort, its ROI vs safety for your family.  If you make a house tight which you should, you obviously need a controlled way to bring fresh air in.

Lbear, there are plenty of wood homes that are tight enough to need supplemental fresh air intake, existing and new without spray foam. So let's say Nick air seals his home and makes it really tight, and then he moves in with new carpet, particle board cabinets, some MDF trim. Initially the house will off gas all the chemicals in a house from all the crap we put it in, and your recommendation is ignore ventilation because it's a wood frame without spray foam so it leaks enough?

That's really a poor, unqualified response, especially the last sentence; you should remove it. At least add something about having a blower door test or something.

BTW: Atlas Rboard has a permeance of less than 1 , making it class-II vapor retarder. This becomes an issue when you have poly vapor barrier on the interior- a classic moisture trap, which becomes even more of an issue with reservoir-claddings like masonry/stone/fiber-cement, since the high summertime moisture drives into the stud bays can't relieved by the drying influence of the air conditioning. Since you're not putting up enough exterior R to be able to skip the interior poly, it's better to use an insulating sheathing with higher drying capacity, such as 3/4" EPS or XPS (something with a permeance of at LEAST 1.0- 2+ is better) and at least 3/8" of rainscreen between the foam and the HardiPlank or Stone, at which point you can skip the interior poly, and it can dry well in both directions. Per IRC 2009, in zone 6 a 2x6 wall with vented cladding you can skip the interior vapor retarder, but that would not apply if you've blocked the sheathing from drying into the ventilation space with a class-II vapor retarder like Rboard. Interior latex paint will have a permeance of 2-4, which is enough to limit the wintertime drives. See: http://www.buildingscience.com/documents/guides-and-manuals/irc-faqs/irc-faq-insulating-sheathing-vapor-retarder-requirements

If it's too late to make the change from R-board, use only cellulose for cavity fill (for it's moisture buffering), and Certainteed MemBrain rather than poly on the interior. MemBrain has variable permeance-it's low perm when dry, but as the moisture levels build up in the stud bays increases it becomes more vapor-open, allowing that moisture to be released. In a cold climate the wintertime air is drier, so it behave like a class-II vapor retarder to limit moisture migration from interior moisture drives when the sheathing is at highest risk due to being cold, but gives it much quicker drying capabilities when any accumulated moisture needs to be released. Even with R-board it's still worth at least 1/4" of rainscreen on the exterior to let the siding dry out more quickly. The moisture releases from sun on dew or rain wetted stone or masonry can be quite intense, but of little consequence if that hyper-saturated air in the rainscreen gap is purged by convection currents.

The IECC 2012 prescribes a tightness limit of <=3.0ACH/50Pa for US climate zones 3 through 8 (you're in zone 6), so PLAN on having active ventilation, preferably HRV or ERV. (In southern WI use ERV if you intend keep the summertime interior RH 50% or less.) Getting to that level doesn't require insulating with spray foam, but it does take at least SOME detailing and test/remediation. Using high-density blown insulation helps. If you're using true vapor barriers like foil facers or poly interiors it's probably best not to use wet-spray cellulose. Dry-blown dense packing (to 3.5lbs per cubic foot in WI) works, but is more labor & expense than lower density wet-spray. The alternative would be to use dense-packed Optima or Spider (1.8lbs min.).

Nobody asks about insulation or air tightness when buying a 10+ year old home, true, but how the place FEELS on a walk-through makes a difference. High-R homes with active ventilation feel "clean", quiet, solid, and comfortable no matter what season or weather. And that's

Nick_M said:
"I am considering doing additional air sealing between all the joints on the inside of the cavaties where the studs meet the sheeting. Is this overkill or does is make sense to do that? If I do it, what is the best method to do it for a DIYer? There are some nice systems out there like Knauf & Owens Corning but that is not available to me."

The Knauf EcoSeal is available to DIYers. The Owens Corning product is not. The Knauf EcoSeal requires a rather expensive pump-type airless paint sprayer to handle the thick EcoSeal product, but it might be possible to rent a suitable sprayer.

Nick_M said:
"Here is the reality on energy efficiency and resale value of a home that is not new (i.e., >10years old). Home buyers don't care! In 15 years when we sell the house, no one will ask what insulation is between my walls or the U value of my windows."

I don't sell a lot of houses, but the last house that I sold, the buyer wanted to see the last two years of utility bills.

Lbear said:
"What I am saying is that when you actually ask homeowners with net zero or LEED homes, what they ACTUALLY PAID for all the "green" energy add-ons, it can EASILY approach the $100K range. When you have geothermal setups, PV's, high-performing windows, etc., you can EASILY get into the $100K range."
The additional cost to convert my modest-sized (1600 sq. ft.) house into a near net-zero source energy house was $28,315, and none of this was DIY, but rather professionally installed. Payback varied from zero to 42 years for the various changes. See http://www.residentialenergylaboratory.com/costs.html for details. Some changes, such as exterior foam on the walls should also improve the longevity of the house by reducing chances of rot in the OSB sheathing.

The added cost could probably have been reduced to $22,080 if I could have dealt with the building inspector more easily, but I was out of state for the build. Careful cost/benefit analysis (and avoiding the BMW approach) at each step can control costs to levels that make economic sense.

Posted By Nick_M on 01 Mar 2012 11:32 PM
Here is the reality on energy efficiency and resale value of a home that is not new (i.e., >10years old). Home buyers don't care! In 15 years when we sell the house, no one will ask what insulation is between my walls or the U value of my windows. They will want to know if the layout, size and what's in the house is to their liking. I know this because my wife is a Realtor and this is what people want to know. She has never had anyone ask her about insulation type or R value and how the home was air sealed or U value of windows and most homeownerse would proably not even know those answers. Thus, for me and most people building a home on a budget, it truly does come down to ROI with a small level of deviation for comfort.

I do really appreciate the suggestions people are making. Unfortunatly, many of them are either too late to do (house is being framed with sheathing and Tyvek already added to exterior walls) or the cost adder of the suggestion is way beyond our budget. I will still be looking at the possibility of doing a blown in type insulation in the walls and maybe upping the attic from R42 to R50.

Sorry to change topics a bit but, ironically, we have another important decision to make that hits ROI vs comfort issue again. The energy consultant is saying that we either need a bath fan to run continuously at 80cfm or I need to add a HRV or ERV in order to get more fresh air in the house. My guess is that I will never see the ROI on the HRV/ERV in 10-15 years living there in comparison to continuous run bath fan. But then I have to weigh the comfort of having a bath fan run continuously, even if it is a super quiet one. Feel free to chime in on this one.

I do believe that in the future people will pay more for energy efficienct homes. It will grow slowly over time. There are productin builders that are building homes that are very energy efficient, even including PV panels. They cost more to build and buyers see the benefits. This will be a growing trend. Some MLS's around the country are including fields for energy efficiency. This will spread across the nation. Since your wife is a RE agent she has probably run across plenty of homes the have rooms that are uncomfortable. Homes were people complain the 2nd floor is to hot in the summer. At times people live in uncomfortable conditions because it costs to much to keep the thermostat at a comfortable level. Dont you think these people would pay a more for a house that cost less to heat and cool and is more comfortable.

It's easiest to cost-reduce a highly energy-efficient building envelope at the design phase. Once you're already well into construction you can still do a lot around the edges, but big changes cost more money, and can create follow-on design issues. Eg: Post-insulating a foundation after its poured to R20 is usually more expensive than doing it with insulating concrete forms on day-1, and if you want your drain-planes to line up with or be slightly outside of the foundation foam to avoid the big Z-flashing step out you then have to re-engineer a cantilevered sill plate that hangs over the foundation foam, and the retrofit still leaves a thermal & hygric bridge of the foundation wall to the footing to deal with. But once you already have the siding & windows & wallboard up the costs of some measures grow exponentially.

At the design phase you can usually demonstrate the net balance of cost on the tighter higher-R envelope against that of the now-reduced size & cost of the mechanical systems, and run your 10 and 15 year net-present-value analysis against the whole package cost, the cost of the increase to the mortgage, and the reduced operating cost. Yes, it's possible to be ridiculous and overspend (say R40 walls using all 2lb spray foam plus an oversized geothermal heating & cooling system where a 1-ton mini-split would have sufficed on a house that tight & high-R) but that doesn't mean you HAVE to.

Even though the Tyvek is up doesn't mean it's too late to increase the exterior foam to R13 and skip the interior poly. The ROI of U0.20-0.25 windows rather than code-min windows is also probably realizable in a 15 year time frame on a combination of savings on HVAC unit cost & operating costs. Being smart about it and specifying the south facing windows for a higher solar gain factor can be very cost effective too. You still might be able to replace some number of operable windows with very tight fixed windows, and going with (almost always tighter) casement or awning windows rather than double-hungs etc. at relatively neutral cost too. But "build first, design later" on the energy aspects is a headache, no doubt, and limits your possibilities.

ERV/HRV systems aren't super-expensive to install if done during construction, and in a WI climate you probably WILL reap the full financial benefit strictly on utility savings over a 15 year period, especially if you want to run higher ventilation rates at times. You'll reap a more subtle but still real financial benefit of healthier indoor air, but that is difficult to quantify, and will vary individually. (How do you know when you saved a trip to the ER for an asthma attack that you DIDN'T have, or a lung infection that DIDN'T occur?)

I do believe that in the future people will pay more for energy efficienct homes. It will grow slowly over time.

There is no question that the interest in energy efficient homes is growing slowly over time. However, the growth is more closely related to the relative cost of energy than any desire to be "green".

For example, if the price of energy rapidly doubled or tripled, the interest would markedly increase, too.

Until then, a small number of homeowners will continue to build the energy-efficient homes they want because they are so rarely found on the market.

Still waiting to see the advent of "Energy Efficient Homes" sections in the local Real Estate mags.

Some MLS's around the country are including fields for energy efficiency.

Is that "Energy Star" or something else?

Posted By ICFHybrid on 03 Mar 2012 10:15 AM

I do believe that in the future people will pay more for energy efficienct homes. It will grow slowly over time.

There is no question that the interest in energy efficient homes is growing slowly over time. However, the growth is more closely related to the relative cost of energy than any desire to be "green".

For example, if the price of energy rapidly doubled or tripled, the interest would markedly increase, too.

Until then, a small number of homeowners will continue to build the energy-efficient homes they want because they are so rarely found on the market.

Still waiting to see the advent of "Energy Efficient Homes" sections in the local Real Estate mags.

Some MLS's around the country are including fields for energy efficiency.

Is that "Energy Star" or something else?

Regarding MLS, I am not sure what is being put in the MLS. Other forums I have been on it has been commented that energy efficiency is starting to pop up. I do know that from my time being a realtor is that the MLS is run at the local level. Each local board decides what gets into the MLS. It is the local demand that influences the value of a certain item and the agents want to be able to search and find homes for buyers that include that item. To me this points to a market demand for energy efficeincy in certain markets. IF you look at building science you see that years ago the materials were different and that we pumped so much heat/cooling into a sctructure it overcame some design/construction problems. As we switch materials and insulate we are finding more issues with mold and deterioration. Poor implimentation and half a@@ attempts at energy efficiency has let to a lot of costly errors that increase the cost of ownership. If you take the right steps in constructing the home you will build in durability as well as enery efficiency. Back venting of siding will greatly improve the life of the siding and the paint will last a lot longer. Joe L at BSC had paint that was in good condition after 16 years. What is the cost savings of painting once every 20-25 years. What is the cost savings of not having to repair siding? As more and more houses have these features word will grow. People will see the value. In the future you will look at the energy bill of the house you are going to buy and when you see that it costs $1,000 or more dollars less per year for utilities then the buyers will pay more. In a way I think it already happens in todays market. I think a segment of the market looks at old homes as being uncomfortable and too costly to heat and cool. Thus they eliminate them from consideration. Others view it as the price you pay to live in an old house. It will be hard to say what will happen in the next 15 years but I think it will move to more energy efficiency. Will it pay to build net zero, I doubt it. But it will pay to build better than code minimum.

In the future you will look at the energy bill of the house you are going to buy

Exactly. And "the future" is determined only by the price and affordability of energy. That future would be tomorrow if energy prices tripled overnight.

Each local board decides what gets into the MLS.

The Real Estate sector doesn't have a clue as regards energy efficiency. They will say or do do anything if it will sell a house. I looked at a tour of homes only a few years ago that were touted as "green" and "energy-efficient". Tthey were large, expensive, code minimum homes with lots of signs up talking about low VOC adhesives for the floor coverings and pointing out Energy-Star appliances. The largest of them proudly proclaimed "DUAL Gas Furnaces". Mmmmmm....now that's luxury for ya.

Posted By ICFHybrid on 09 Mar 2012 07:35 AM

In the future you will look at the energy bill of the house you are going to buy

Exactly. And "the future" is determined only by the price and affordability of energy. That future would be tomorrow if energy prices tripled overnight.

Each local board decides what gets into the MLS.

The Real Estate sector doesn't have a clue as regards energy efficiency. They will say or do do anything if it will sell a house. I looked at a tour of homes only a few years ago that were touted as "green" and "energy-efficient". Tthey were large, expensive, code minimum homes with lots of signs up talking about low VOC adhesives for the floor coverings and pointing out Energy-Star appliances. The largest of them proudly proclaimed "DUAL Gas Furnaces". Mmmmmm....now that's luxury for ya.

I agree that agents are not a highly ethical group and many will do whatever it takes to make a sale. But they also react to what the market demands. In some parts of the country that have a higher demand the MLS reflect the demand. Tell me why and how energy prices should triple. Very little oil is used for home heating so home energy is not tied to oil. Gas and electric is from dosmestic sources. There is a level of improvement in construction that does make sense from an energy savings standpoint and should be encouraged.

I said "IF" energy prices tripled. It wasn't intended to be predictive or political.

The point is that interest in energy efficient homes is tied to the cost of the energy. As long as energy is perceived as cheap, no one will want to spend any money being more efficient. Those dollars will go to media rooms and granite counters and people will continue to "waste" the energy.

My house is very tight (612cfm50) 1.464 ach50 (NYS code is 7 ach50, eStar is 5 ach50 and Passive House is .6 ach50 - just to give you some points of reference). In a tight house you have to control air exchanges and humidity. It is surprising just how much humidity is generated in an airtight house.

I spend a great deal of time actively managing air changes and even more particularly, humidity. Unless you want to be intimately involved on a day to day basis in a manual way, get an HRV. Just running a ventilation fan is only half of the equation - you need a way to intake fresh air, and you are going to want a way to pre-warm that fresh air in the coldest months. I am using a combination of solar pre-warming, manually turning the ventilation system on and off depending on the amount of sun, and using a dehumidifier when the outside air is not dry enough to decrease the humidity inside the house, or there is not enough sun to prewarm the cold winter air. Sometimes (such as when I am cooking at night and using the range hood) I just open a window and let in cold air to make up for that which is being vented out. I don't think most folks are willing to be so actively involved, so an HRV is necessary.

-Rosalinda

As long as energy is perceived as cheap, no one will want to spend any money being more efficient. Those dollars will go to media rooms and granite counters and people will continue to "waste" the energy.

I agree 100%. When you consider all the costs, energy in the US is highly subsidized (aka wastefully cheap). This is a terrible policy that could be fixed with taxes (and credits to remain $ neutral for the average person).