We are planning on building a house in a year or two. Just found this great forum and would like to build a energy efficient house.

Given:
Near Baltimore Md.
Three story house
28'x60' floor plan
Waterfront on the 28' side. (Very Windy)
Lower than normal (for the region) airconditioning needs in the summer due to a wind off the Chesapeake bay. But want a good a/c system when the wind stops.
First floor will be a garage and unfinished space due to code for flooding (Chesapeake bay). Most likely pored concrete 10' foundation. 
We plan on living here forever.
No natural gas available.

Geothermal might not be allowed due to Chesapeake bay environmental issue's and size of lot. 50x300. As a first step I called a geothem installer... figure they would know. waiting for a call back



Question:

We are planing on building a house in a year or two. We want to build a above average energy efficient house but not to an extreme. I.E most bang for the buck.
I am really in the gathering information stage. Just want some ideas as to what to start researching given the information above...I.E  types of construction, Insulation, HVAC, Windows, Roof ect...


Thanks

Mark

First, it sounds like you have started in this direction but get full information about government requirements and restrictions for the piece of property.  Zoning setbacks, building height, impervious area, parking, etc, etc.   Is there a HOA?  If so make sure you know exactly what their restrictions are too. 

Define your budget, and be realistic.  Remember that when building a house there is always going to be unexpected expenses - unless you have already built that same house plan before, and even then things can come up, like volatile building material prices.  I'd say, maybe put 10% in reserve.  At the very least if everything comes out perfect (it won't) you will still have money to buy furniture to put in the house and food in the pantry cabinet.  This includes talking to bank's to find out about financing - assuming our need that...  These days banks have very specific requirements, and building has always been a question mark anyway.

Get a hold of a checklist from a green building program. My recommendation is the NAHB green program. The actual checklist is a spreadsheet on their web site, but you can buy a book or 2 that state the standards and requirements and explain them.   This will help you learn about the different elements that go into building a green home.  Even if you don't want to utilize such a program it will be an educational tool for you.  BTW - I did a survey of green building programs and like the NAHB one because it is very value oriented.

Re the energy efficiency find out about the Energy Star for Homes program from the US EPA.  Again, check out their web site.  This will help you get some ideas about energy efficient elements, and again they have checklists that are used later to verify that the house is built to at least minimum energy efficiency standards.  This is normally done by a HERs rater who essentially verifies the house is built to the minimum which is currently 15% better than a standard house.  Even of you want better overall performance than this, you still need the minimum as a foundation - for example, what good is a PV solar system (for example) if the house's insulation job doesn't have a fully aligned air barrier.  Not that you are supposed to know what that means, but it is just and example of what you need to learn.  If you get involved with an Energy Star HERs rater later during the design stage they will help you determine which energy design/implementation enhancements will produce what % of energy efficiency. 

During your research of different features you need to find $ numbers (not easy) on the cost of various upgrades you are interested in.  For example you could have someone design a super insulated passive solar home with a ground source heat pump and then when you find out the upgrades will cost $70k (really wild guess) the whole thing could be off the table as it isn't in the budget.  What happens with these energy upgrades is the cost tends to escalate quickly - ie you can MAYBE get the first 15% at $100 a point. The next 10% at MAYBE $1,000 a point, and the next 10% at $10,000 a point!!! OK - the last one is exaggerated but you get the idea.

The above will just give you some ideas.  Now, find a design professional who has specific experience in green, energy efficient homes.  All don't, although most might claim they do.  HE/She will know how to combine different design requirements, green, and Energy Efficient elements to produce a cohesive design for a house that acts as a system rather than just a bunch of independent ideas all thrown into the same box.

BTW - are you planning on being an owner/builder, hire a design build, hire a designer and then a builder or what? I know this is might still be up in the air but we need an idea.

If you have any specific questions about the above just ask. 

One last thing - take any advice you get here or elsewhere on the Internet with a grain of salt - you really don't know who you are dealing with and sometimes people talk a good game but don't actually have background and/or experience in the areas being discussed - but you already knew that...

PS - my family has a house on the bay near Deal MD. I grew up spending my summers there. Fond memories.

Mike,

Thanks for such a informative response. We are in the process of getting a variance now. And I will take your advise and look for a design professional who specializes in green homes.
Just to add...
Fortunately there is no HOA.
We are planning on hiring a architect/designer and will be the owner/builder. I am planning to attend a two day owner/builder workshop to learn more about SIP's from sipschool.org.
We aren't going to look into solar right now but we are planning on building the infrastructure into the home so when the costs per KW go down it will be an easy upgrade.
Are current design takes into account for the Chesapeake Bay Critical Area impervious surface limitations.

Thanks again,

Mark

Here our community college offers classes in green building at a very affordable price.  Not that I think you would get in depth knowledge out of that but they would undoubtedly expose you to the different technologies, some of which you may not be aware of.  Perhaps something similar is available where you live.

Here are 2 of my suggested green house ideas:

LIGHTING Recessed LED lights by Permlight draw 33 percent less electricity than already thrifty compact fluorescents.

HEATING Radiant heating tubes--fed by an Apricus solar water heating collector on the roof--snake through concrete floors, warming the home's interior.

The biggest bang for the buck is almost always passive solar. That's because passive solar systems utilize parts of the house that you already have to have; it's mostly how you orient the house, put the windows, length of overhand, etc. Overall % of heat/cool needs depends on location; here in CA orientation and good passive design can cut heat/cool by 40% or more without any added cost. Your results may vary.

Air infiltration measures are a big value. I like masonry construction for added thermal mass, fire resistance, and no termites. Those are more qualitative values that are hard to measure, but are worth a lot to me at minimal added cost. You will find a lot of proponents of ICF; I happen to like concrete or CMU with surface bonded concrete that can minimize need for interior drywall.

You could spend days reading this site and others exploring various styles, designs, and systems. As far as doing the owner/builder thing, check a website at www.byoh.com. There is a lot of information; pros and cons, about DIY there. Owner-builder financing is especially challenging these days.

For me a concrete dome , earth-sheltered, offers the best combination. See monolithic.com.. But the different shape, appeal and challenge on financing and resale may be to much for many to overcome. So that's my 2cents.

That's a mild climate. You have a lot of options.

Since you are already looking at concrete with the flood zoning, in-slab radiant would be a logical choice. I wouldn't have geothermal high on the list. You could get away with a passive solar and one of the new efficient air source heat pumps to drive some radiant heating. You could do a ductless mini-split to provide precise heating and cooling to 3 bedrooms upstairs and maybe even some main floor air conditioning.
Quality windows that seal well would be important with that exposure.
Make sure you create a "heat stack" which you can utilize to passively cool the house. That is an open path to the upper area and vents or opening windows to exhaust the heat. You might even consider placing the top vent exits in such a way that you can utilize the onshore breeze to drive the breezes through lower windows.
If you are thinking about solar panels later, make sure to provide both roof attachment points and conduit or spaces to run the cables and pipes. It's much easier to do during new construction.

Because you have so many options, you might want to contract with an engineer to model the energy loads in advance of making final design decisions. That will give you the ability to run calculations several different ways to see what makes sense. For example, I was going to use foam exterior sheeting to isolate the studs until an analysis showed that the difference would be about $10/year in heating costs. That saved a fair amount of effort right there.

From a "...most bang for the buck" point of view, air-sealing the building envelope is the single most cost-effective energy efficiency detail, and it shouldn't be left to chance or done primarily after the fact. Defining the primary air barrier in the design phase from the foundation to the ridge top is key, as is IMPLMENTING the design during construction. Using air-tight methods caulking foundation sills, exterior sheathing, studwall plates etc as you go reduces the amount of detailing labor for sealing it after the fact. (Tremco acoustical sealant seems popular with some builders, but there are plenty of alternatives.)

Insulated concrete forms for the foundation are inherently air-tight (reducing the amount of air-sealing detailing required), and cheaper than many other foundation methods. It's a cost-ADDER for above grade walls though, and is an expensive way to go high-R, but it's a very sturdy way to build a house (which can be important in coastal hurricane zones.)

If stick-built, going with high density low-cost sprayed fiber insulation is more expensive than batts, but usually worth the (very small) premium. Spray foam, not so much, but spray foam can help with air sealing if those details were skipped. Closed cell spray foam can be cost effective for adusting vapor-retardency and air sealing in small doses, but is very expensive as a total solution. An inch of closed cell foam on the interior of the sheathing protects the sheathing from winter moisture accumulation , but may not be "worth it" in your climate if you've air-sealed the sheathing, use cellulose in the cavites, and provide at least a 1/4" rainscreen gap between the sheathing and siding (to enhance drying capacity of the wall.)

If the shape size is relatively simple, utilizing Advanced Framing Technique (http://apps1.eere.energy.gov/buildings/publications/pdfs/building_america/26449.pdf ) is cost effective, and reduces the thermal bridging of the framing considerably for better thermal performance. Even if only a subset of the those methods are used, note that 2x6" 24" on center studwalls have about the same board-feet of lumber as 2x4s 16" on center, with similar structural characteristics. It's fewer boards to cut, less labor, and adds ~ R7 to a fiber insulation cavity fill. The corner detailing of AFT is almost always possible, improving thermal performance there as well.

In the mid-atlantic it's usually an easy financial argument for adding 1" of XPS insulating sheathing over 2x6" studwall construction. It adds R5 to the the center-cavity R, but more importantly it cuts the heat loss at the thermal bridging of the studs literally in half, for a ~30% boost in thermal performance/$

Cooling loads in Chesapeake Bay are predominantly latent (humidity), not sensible (temperature). Don't expect too much "free" cooling from those temperate maritime breezes. You may be able to cool the house down temperature wise, but on many days removing the humidity introduced that way will be more expensive than the sensible-cooling energy saved. Use of mini-splits or air-source heat pumps with dehumidification mode (or a whole-house dehumidifier) may prove to be a better strategy. Making the house air tight and ventilating with ERV (energy recovery ventilation that transfers both heat & humidity between the incoming & outgoing exhaust streams) will also reduce latent-cooling costs. Designing the walls and windows for low summertime gain is key to controlling sensible-cooling costs. Going high-R on the walls and designing in some thermal mass to the interior doesn't hurt either, but glazing is often the make or break on cooling.

With an ~R20 nominal wall, the fraction of glazed area and window type can begin to dominate heating/cooling load factors. Designing south side overhangs or awnings to minimize mid-summer gains can be important, and allows you to use more glazed area for passive solar gains in the winter. Minimizing the glazed area on E/W/N sides can be significant. Casement and awning windows seal better than double-hungs & sliders, and casements offer more egress area per amount of glaze area for bedrooms than double-hungs & sliders. Using non-operating windows where opening isn't needed seals better still, and is even cheaper than casement/awnings. (Opting for narrower rather than shorter casements where egress is needed, and high-mounted shorter/wider awning windows where daylighting is desired but not the view or solar gain works for most. YMMV.) Think of every window as an R2-R3 hole in your R20 insulation, and be conservative. Going with Energy Star rated windows suitable for aspect & climate usually has an easy economic argument over code-minimum for new installation. Going a lot better than that is po$$ible, but it's usually just cheaper to use smaller/fewer windows to get the same thermal performance out of the building envelope as a whole.

Geothermal will have a very high up-front cost and may never pay off. Before adding $15K+ or more to the cost of mechanical systems, look at what adding the same money to a tighter and higher-R building & window package would deliver. Air sealing to <1.0 ACH/50 (air changes per hour @ 50 pascals pressure) and boosting the R-value to R30+ can often be cheaper if you design carefully, delivering more bang/buck. If you DO go higher-R on the walls, pay attention to thermal bridging at the foundation, and put at least R8 of EPS (bead-board- cheaper than XPS) under the slab.

Some reading while considering your design:

http://www.buildingscience.com/documents/reports/rr-0903-building-america-special-research-project-high-r-walls

http://www.buildingscience.com/documents/reports/rr-1003-building-america-high-r-foundations-case-study-analysis

but more importantly it cuts the heat loss at the thermal bridging of the studs literally in half, for a ~30% boost in thermal performance/$

Dana, I agree with you on this, but I also want to point out, for the benefit of those who haven't thought about this as much, that we are talking about 30% of a portion of the heat load. For example, there are the heat losses from the foundation, the ceiling and the windows (which further reduce the affected wall area) and, of course, infiltration. If you assume that these are all roughly equivalent for the purposes of illustration, you now have the improved wall representing 30% of 1/5 which is down to an actual difference of 6% in heating costs.

If you assume the cost to heat a place is $1,500 yearly, you have to decide if the cost of adding the foam is worth 6% of that or $90/year. Variable factors all conspire to move this "price point" around, but it usually goes lower once the designer gets interested in energy efficiency. With my new build, we used stick framing on the second floor in order to avoid extending the ICF to over 30' high. As a "hybrid", that meant the stick framed portion represented an even smaller percentage of the total wall area. So, what started out as a slam dunk (applying foam) with the architect and me, came to a screaming halt when the heat engineers ran their models. I think the difference came to less than $10 a year making the payback time on foam about 180 years.

Mild climates increase this difference, making foam less cost-effective.

Similar things happen with certain construction methods. They might be promoted as costing "only 5% more..." but the sticker shock comes when the buyer realizes that is 5% of the total build price, not 5% of just foundation or framing........

This is why I am increasingly a fan of energy modeling. Once the model is built, it is relatively easy to make a change in say, the R-value of the wall, and get some idea of what the total overall impact is.

I get what you're saying- I too am a fan of energy modeling for optimizing value is a good thing, but selling high-performance buildings on energy savings is a losing proposition literally 100% of the time. In a 10 year NPV financial analysis you can't even rationalize code-minimum R values ( but you usually can in 20-25 years.) The average 'merican will sell it to the next sucker in 6 or 7 years, so why even build to code minimum if there's no "payback"?

Analyzing it only on NPV of the energy savings you'd never be able to sell minimum-R ICF construction in that climate either, and that too would be a mistake. An R16 ICF would be more comfortable, more durable, and perform measurably better than a comparable-tightness R19-batt insulated 2x6 no-foam house, which is probably the code-minimum in Baltimore. But that too would cost significantly more than the standard code-min stick built house (and in most cases, cost more than an advanced-framing air-tight 2x6 cellulose + foam house that would beat it on comfort & energy efficiency measures.) That's not to say there aren't many other advantages to going ICF for 1 & 2 story houses.

With exterior foam on stick-built you're adding more than R-value- your adding resiliency to the building by better protecting the structural wood from moisture, and you're adding COMFORT by better bounding the temp of the interior surfaces, making it more comfortable at both higher/lower room temps when under cooling/heating load extremes. The 97.5% heating outside design temps for Chesapeake Bay locations are in the low to mid-teens F (13F for Baltimore)- maybe not brutal by upper midwestern standards, but might challenge the notion of "mild climate" for some. This isn't San Fransisco Bay, or even Puget Sound style temperate climate- it drops below 0F every decade or so, and single-digit seasonal lows aren't rare.

The design goal here was to "...build a above average energy efficient house but not to an extreme...". This is a ~5000' house with ~5000 square feet of exterior wall surface (before subtracting for windows & doors). Adding an inch of XPS or iso to the walls isn't extreme- it's code-minimum in some places not all that much colder than Baltimore.

To be sure it's not the energy-savings bang per buck that you get out of simply building with air-tight methods and minimizing the square footage of window area. Building air tight is cheap, and going with smaller simpler windows even cost-negative, but R5 in exterior foam is still recommended for a stick built structure with a mid teens heating design temps, and January mean temps that can be as low as the high-20s some years. (see: http://weather-warehouse.com/WeatherHistory/PastWeatherData_BaltimoreCustomsHouse_Baltimore_MD_January.html )

In that climate R5 on the exterior of a 2x6 fiber-insulated wall it pretty much guarantees that the structural wood never accumulates winter moisture even from the interior side air leaks, allowing you to eliminate interior vapor retarders, enhancing the overall drying capacity of the the assembly. In my mind it's "worth it" from that aspect alone, but the comfort-aspects of warmer walls when it's sub-20F in the AM (or cooler walls on a 100F July or August day) is also a plus. The ~R5 thermal-bridge of a 2x6 stud is something that can be felt with your palm or wrist on a gypsum clad interior wall when it's 10F out if your looking/feeling for it, but not so much if foam-clad.

Regarding geo- before sinking an extra 20 grand over what a more modest heating/cooling mechanicals would cost, consider how much in better windows & more exterior foam that might buy you and the relative impact on utility costs. (This is one where careful energy modeling is VERY useful.) If you boost the envelope design to where the total heat load at 13F is under 30KBTU/hr there is a middle road using the Daikin Altherma hydronic air-source heat pump and radiant floors/ceilings which would be a HUGE boost in overall comfort. It's very pricey for an air-source heat pump, but it has a higher COP more similar to geo-type numbers, and still puts out 27KBTU/hr at -4F without kicking on the auxilliary heat strip. It'll get much higher average efficiency if you can keep the water temp requirements under 100F, which means you can't really use cheap fin-tube baseboard, but it's worth doing the math on before jumping into geothermal. There's usually no payback on radiant floors either, but if "...living here forever" means you want to max out the cush-factor, higher-R walls and radiant floors are both more comfy, and use less energy, and are cheaper to install in new construction than as retrofit.

But if you were planning to just touch up the paint and flip it in a few years when the housing market recovers, fuggdabout it (all of it!)- there's no payback on exterior foam or air-tightening or better windows or higher-efficiency mechanicals compared to what you'd get out of buying nicer kitchen & bath amenities when it comes to resale.

Dana1,

I am afraid that you are right.  People do not value long-term savings against initial cost when they can have the bling that everyone can see. 

Additional cellulose is cheap, an extra 12 inches for about $1 per foot for an additional R-38. Having this additional space designed into your truss package cost very little additional. A double 2 by wall filled with cellulose is also cheap. A contractor grade triple pane window is also relatively cheap. Using radiant cool roof and radiant barrier is again cheap. Sealing completely is also inexpensive. All of the above should cost less than $5 extra per foot, will cut noise in 1/2, eliminate drafts and cut the size of the heating cooling equipment by 1/2. Costs an extra $25,000 and save $10,000 in reduced equipment sizing. $15,000 financed over 30 years is $85 per month and the utility savings will be similar will be more on day one. The interest will be deductible as well. Note that this is a fixed cost. Energy costs will increase over time. This means day one is a wash. In 10 years the savings will be $100 a month or more and in 20 years it will be $200 per month or more. What part of this does not work?

Foam is more expensive, some window manufacturers will want more, but I have done the above on projects for this type of costs for my clients.

Brian

Posted By zehboss on 27 Feb 2011 10:08 AM
Additional cellulose is cheap, an extra 12 inches for about $1 per foot for an additional R-38. Having this additional space designed into your truss package cost very little additional. A double 2 by wall filled with cellulose is also cheap. A contractor grade triple pane window is also relatively cheap. Using radiant cool roof and radiant barrier is again cheap. Sealing completely is also inexpensive. All of the above should cost less than $5 extra per foot, will cut noise in 1/2, eliminate drafts and cut the size of the heating cooling equipment by 1/2. Costs an extra $25,000 and save $10,000 in reduced equipment sizing. $15,000 financed over 30 years is $85 per month and the utility savings will be similar will be more on day one. The interest will be deductible as well. Note that this is a fixed cost. Energy costs will increase over time. This means day one is a wash. In 10 years the savings will be $100 a month or more and in 20 years it will be $200 per month or more. What part of this does not work?

Foam is more expensive, some window manufacturers will want more, but I have done the above on projects for this type of costs for my clients.

Brian

Double studwall construction is only "cheap" when looking at much higher R-values than code minimums. If the stated design goal is to do better than "average" or "typical" without going hog-wild I doubt that approach is going to make sense here.   Air sealing and sprayed/blown cavity insulation alone might be enough meet that very non-specific goal.  Double studwalls are a relatively cheap & easy way to go high-R, but it adds a significant fraction to framing labor costs. At less than 1.5x code minimum on wall-R it's usually cheaper to use foam sheathing.

Also, radiant barrier is "cheap" only when treating a low-R roof with ducts above the insulation layer. See:  http://www.ornl.gov/sci/ees/etsd/btr...et2010.pdf In most instances putting the money into deeper cellulose at the attic floor would have a better ROI.  A code minimum attic is R38 in Baltimore- adding RB to even a code-min level of roof insulation where there are no attic ducts has effectively zero cooling season benefit, and even less during the heating season, whereas the effect of bumping up the cellulose even an inch or two above code min would have a measurable effect, both winter & summer.  R50 or even R60 in blown cellulose is pretty cheap in attics and has a favorable net-present-value if designed in from the get-go in that climate.  Radiant barrier, not so much.

Similarly, going with cool roof material in Baltimore only makes sense if it's a low-pitch (under 3:12) or flat roof, or when it's cost-neutral on the material.  Otherwise, spend the money on deeper attic cellulose. 

On a flat roofs or cathedralized ceilings, put sufficient rigid EPS above the roof deck to be able to fully fill the rafter bays with cellulose without having to ventilate the roof deck.  That provides a  thermal break over the rafters, and allows you to skip the interior vapor retarder for a more resiliant & faster drying roof stackup.  In Baltimore it would take no more than ~10-15% of the total R as foam, which would take only 2" of EPS above the roof deck to get to ~R50 unventilated, with 2x12 rafters and blown cellulose.  Rigid foam is an expensive way to go high-R, but at the minimums required for added moisture-resiliance still worth it in stick-built assemblies.  Being able to avoid roof deck ventilation on  flat or cathedral roofs simplifies the air-sealing of that critical assembly.

Triple-pane windows- maybe. On bigger windows where you want the view, yes-  otherwise going with less window area using double-panes to achieve similar or lower total heat loss/gain as a larger triple pane is cost-negative, (not even a slight cost-adder.)  Fixed windows, and keeping with awnings & casements (no sliders or double-hungs) for the operable windows for better air tightness, and to provide larger egress area per square foot of glazed area on bedrooms.  (Sliding doors are also significantly leakier/harder to air seal than standard doors.)