Things You Do Not Need

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Things You Do Not Need

And a few things you do

Posted on Feb 9 2018 by Martin Holladay
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Houses are changing. Anyone buying a new home in 2018 expects the home to be quite different from one built in 1918, of course.

What “new features” is the typical buyer of a new home seeking out? It depends. Some buyers are looking for a foyer with a 20-foot ceiling and a master bathroom with a big Jacuzzi. Others, including the typical GBAGreenBuildingAdvisor.com reader, are looking for low energy bills and superior indoor air quality.

A beautiful house from 1918 probably included a large coal bin in the cellar. These days, coal bins are obsolete. If you want your new home to be green, then you probably realize that many of the must-have features of decades past are as obsolete as a coal bin.

Features you do not need

Some of the features listed below were normal (or even desirable) in a house built a few decades ago. In a green home? Not so much.

A vented crawl space. Unless you live in an unusually dry climate, a vented crawl space is usually damp and nasty, especially during the summer. There is no longer any justification for building this type of foundation. Instead, build on a slab foundation or a basement foundation. If you insist on a having a crawl space — and I’m not sure why you would — make sure that it is an unvented conditioned crawl space.

For more information, see Building an Unvented Crawl Space.

Bay windows. Most bay windows leak a lot of air. Moreover, the unglazed portions of a typical bay window often have very little insulation. (If you look at the horizontal ledge that a typical bay window sits on, you’ll realize that this cantilevered platform is too thin to contain much insulation.)

A well-insulated house has as few bump-outs as possible. A bump-out is an energy nose bleed.

For more information, see Green Building for Beginners.

Double-hung windows. Many of us grew up in a home with double-hung windows. They’re charming. They’re also leakier than casement windows or awning windows. It’s time to bid the double-hung window adieu.

For more information, see How to Order Windows.

Sliding glass doors. Sliding patio doors have the same problem as double-hung windows: they leak a lot of air. There are several possible solutions, including hinged French doors or lift-and-slide doors. For more information, see All About Doors.

Dormers or skylights. Interrupting your roof plane with a dormer comes with the same disadvantages of interrupting your wall plane with a bay window. A dormer usually interrupts the air barrierBuilding assembly components that work as a system to restrict air flow through the building envelope. Air barriers may or may not act as a vapor barrier. The air barrier can be on the exterior, the interior of the assembly, or both., introducing air leakage, and the resulting bump-out is usually poorly insulated.

Similarly, a skylight represents a low-R-valueMeasure of resistance to heat flow; the higher the R-value, the lower the heat loss. The inverse of U-factor. hole in your thermal envelope. Finally, many dormers and skylights are associated with roof leaks, due either to defective flashing or ice damming problems. So cross these features off your list.

For more information, see Why I Hate, Hate, Hate Skylights.

A furnace or boiler. That big beast in the basement — the furnace or boiler — is no longer required. A well designed green home can be heated and cooled with one or two ductless minisplits. These revolutionary heating and cooling appliances are less expensive to install than conventional types of heating equipment, and they’re usually cheaper to operate.

For more information, see Just Two Minisplits Heat and Cool the Whole House.

A wood stove or fireplace. A warm wood stove evokes fond memories for many Americans. But a wood stove doesn’t belong in a green home. It’s just too hard to balance a wood stove’s voracious appetite for combustion air with a modern home’s need to limit air leakage.

For more information, see All About Wood Stoves and Brick Chimneys With Multiple Flues.

A chimney. If your house doesn’t have a furnace, boiler, wood stove, or fireplace, it doesn’t need a chimney. That’s good news — because a chimney represents a big thermal bridge and a path for air leakage.

For more information, see Farewell to the Chimney?

A gas-fired kitchen range. You’ve probably heard someone say, “Real cooks prefer a gas range.” There may be a few holdouts out there, it’s true, but green builders know better. Once you’ve learned about the indoor air quality problems associated with a gas range and the climate change problems associated with natural gas leaks, you’ll learn to love you electric induction range.

For more information, see The Hazards of Cooking With Gas and Going High-Tech With an Induction Cooktop.

An attached garage. Due to car exhaust and fumes from stored paint, household chemicals, and cans of gasoline, the air in your garage is nasty. If your garage is attached to your house, some of that nasty air is going to seep into your house. The solution: separate your house from your garage with an open breezeway.

For more information, see All About Indoor Air Quality.

What you need instead

So now you know what your home doesn’t need. To balance the list, I’ll provide my recommendations for must-have features.

Sub-slab insulation. If your house includes a concrete slab — either a basement slab or a slab on grade — you’ll need a continuous layer of horizontal insulation under the slab, unless the house is located in a climate where air conditioning bills are higher than heating bills. In all climates, the perimeter of the slab should be insulated with vertical insulation (unless termite infestation worries make perimeter insulation impossible).

For more information, see Insulating a slab on grade and Sub-Slab Mineral Wool.

An air barrier. You can’t build a home that performs well unless you pay attention to airtightness. The home’s air barrier needs to be carefully designed before construction begins, and transitions between different components — between the foundation and the walls, between the walls and the ceiling, and between the windows and the rough openings — need to be detailed for airtightness.

Finally, the integrity of these details needs to be verified by a blower door test before construction is complete.

For more information, see Questions and Answers About Air Barriers.

A rainscreenConstruction detail appropriate for all but the driest climates to prevent moisture entry and to extend the life of siding and sheathing materials; most commonly produced by installing thin strapping to hold the siding away from the sheathing by a quarter-inch to three-quarters of an inch. . One of the best ways to limit wet-wall problems is to include a rainscreen gap between your siding and your water-resistive barrierSometimes also called the weather-resistive barrier, this layer of any wall assembly is the material interior to the wall cladding that forms a secondary drainage plane for liquid water that makes it past the cladding. This layer can be building paper, housewrap, or even a fluid-applied material. (WRB). A rainscreen gap limits inward solar vapor drive, reduces the likelihood that wind-driven rain will soak the sheathingMaterial, usually plywood or oriented strand board (OSB), but sometimes wooden boards, installed on the exterior of wall studs, rafters, or roof trusses; siding or roofing installed on the sheathing—sometimes over strapping to create a rainscreen. , and helps damp sheathing dry quickly.

For more information, see All About Rainscreens.

A mechanical ventilation system. Does it make sense to open a window when you want more ventilation? No. When you open a window, you don’t really know whether air will escape or enter through the opening, and you’ll probably be wasting energy. In any case, most Americans rarely open their windows, even when indoor air is stuffy and the outdoor air is mild, because it's often difficult to detect when the indoor air is starting to get stuffy.

Every green home needs a mechanical ventilation system to provide fresh air to occupants. For more information, see Designing a Good Ventilation System.

A photovoltaic(PV) Generation of electricity directly from sunlight. A photovoltaic cell has no moving parts; electrons are energized by sunlight and result in current flow. (PVPhotovoltaics. Generation of electricity directly from sunlight. A photovoltaic (PV) cell has no moving parts; electrons are energized by sunlight and result in current flow.) array. Unless you are building in a very shady location, you should plan to include a PV array on roof or in your yard. Even if your local electric utility doesn’t offer homeowners a favorable net-metering agreement, it never hurts to plan ahead for a future PV array. Utility policies may change in the future. (Of course, these future policy changes can go either direction — either raising or lowering reimbursement rates for PV electricity sold by homeowners to the grid.)

If you prefer a roof-mounted array to a ground-mounted array, keep the needs of your future PV array in mind when you plan your home’s roof. The ideal roof for a PV array faces south or southwest, and is free of dormers, skylights, chimneys, and plumbing vents.

For more information, see An Introduction to Photovoltaic Systems.

Martin Holladay’s previous blog: “Condensation on Car Windshields.”

Click here to follow Martin Holladay on Twitter.


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Image Credits:

  1. Image #1: Midwest Construction

1.
Feb 9, 2018 8:56 AM ET

Unvented Crawlspace
by sean bromiley

Hello Martin. I just built an unvented crawlspace. Despite your words of advice against crawlspaces in general, it was quite a bit less expensive than a basement and the grade/soil conditions were such that it seemed to me the logical choice. My questions is about installing a floor register in the floor above to allow air to flow between the living area and the sealed crawl space below. Could that be considered a fire hazard by a building inspector?


2.
Feb 9, 2018 9:04 AM ET

Why a crawl space?
by stephen sheehy

Sean: I understand why no basement, but why a crawl space? What do you see as the advantage of a crawl space over a slab?


3.
Feb 9, 2018 9:27 AM ET

Response to Sean Bromiley (Comment #1)
by Martin Holladay

Sean,
As I noted in my article, Building an Unvented Crawl Space, installing a grille in the floor above a crawl space is a code requirement. The requirement is found in Section R408.3 of the International Residential Code. That said, your local code requirements may vary.

Since the grille is required by code, it's hard to imagine that it creates any fire safety risk. I have never heard of any code official objecting to such a grille.


4.
Feb 9, 2018 9:29 AM ET

Response to Stephen Sheehy (Comment #2)
by Martin Holladay

Stephen,
One advantage of a crawl space over a slab is that a crawl space can be easier (and sometimes cheaper) to install on a sloping site than a slab. That said, I think that the disadvantages of crawl spaces are serious enough to justify the upcharge to a slab (if the slab costs more) or a basement.


5.
Feb 9, 2018 11:13 AM ET

Edited Feb 9, 2018 11:19 AM ET.

Closed Breezeway
by Tyson Godfrey

I'm in the beginning steps of designing a house and we are planning on building a detached garage but with a closed unconditioned breezeway that functions as a mudroom. I was planning on finishing the exterior wall of the house with all of the insulation and air sealing used on other exterior walls before constructing the breezeway. I'm also planning using an exterior door for the entry between the breezeway/mudroom and the house. Any thoughts on if this would be sufficient to address the air quality issues associated with an attached garage? Or should I replan and just go with an open breezeway?


6.
Feb 9, 2018 11:17 AM ET

Crawlspaces
by Malcolm Taylor

Another advantage of having a house on a crawlspace is adaptability. Renovations or repairs are a lot easier in house with a trussed roof and crawlspace, than they are in houses with slabs (or finished basements), and stick-framed roofs.


7.
Feb 9, 2018 1:10 PM ET

Edited Feb 9, 2018 4:21 PM ET.

Response to Tyson Godfrey (Comment #5)
by Martin Holladay

Tyson,
Like many design issues, the issue you raise is a judgment call. If you have an enclosed breezeway between your house and your garage, the breezeway lessens the chance that fumes from the garage will cause air quality issues in the house. An open breezeway is better, but may not be necessary.

The decision hinges in part on (a) whether members of your family are particularly concerned with indoor air quality issues, for medical or other reasons, and (b) the likelihood that you will store paint, gasoline, and chemicals in your garage.


8.
Feb 9, 2018 3:36 PM ET

Edited Feb 9, 2018 3:37 PM ET.

Great List -but have Sliding Glass doors evolved?
by Rick Evans

Great List! Was surprised to see wood stoves on here but it makes sense.

Some "Lift and Slide" Sliding glass doors market themselves as being less prone to air leakage. I wonder how true this is? Anybody getting low ACH numbers with lift and slides?


9.
Feb 9, 2018 4:08 PM ET

Response to Rick Evans
by Martin Holladay

Rick,
You're right -- lift-and-slide doors are less prone to air leakage than old-fashioned sliding glass doors. They're mentioned in one of my articles (All About Doors).

I'll edit this article to include a mention of lift-and-slide doors. Thanks.


10.
Feb 9, 2018 9:43 PM ET

Patio Doors
by Stephen G

Huh. I never even thought about sliding patio doors as a problem.

I knew reading the list that I would be caught in the "sin" of having a natural gas range, but I figured that would be the only one. Never even thought about the doors. Sadly, too late to change now.


11.
Feb 10, 2018 6:13 AM ET

Response to Stephen G
by Martin Holladay

Stephen,
The advice I've given isn't intended to make you feel bad. Enjoy your patio doors. No house is perfect, and life is too short to worry about a little infiltration here and there.


12.
Feb 10, 2018 8:52 AM ET

Floor Register in unvented crawlspace
by sean bromiley

Martin - thanks for commenting on the required floor grill in an unvented crawler. It’s interesting that the code allows for it but also requires areas like that be blocked off with plywood or drywall or something to slow the spread of fire between floors. I suppose I’ll just put a grill about the size of a forced air heat register in the floor and call it good.


13.
Feb 10, 2018 9:02 AM ET

Response to Sean Bromiley
by Martin Holladay

Sean,
Almost every two-story house in the U.S. has an open stairway connecting the first floor with the second floor -- which seems a much more significant air path between floors than a small floor grille. So I think you are misinterpreting the code.


14.
Feb 10, 2018 11:45 AM ET

Sean
by Malcolm Taylor

Code provisions requiring fire-stops and blocking are to stop the spread of flames between concealed-spaces, not within the living area. The idea being they don't want fire that gets into the structure to have a hidden path between the floors, walls and roof. I suppose a case could be made that a hole in the floor above the crawlspace that was under a wall, and connected to a wall grill might meet this definition.


15.
Feb 10, 2018 11:45 AM ET

Ok good point.
by sean bromiley

Ok good point.


16.
Feb 11, 2018 10:04 AM ET

Mini split cost
by Andy Kosick

I love my minisplit system but, at current prices, it's still a little more expensive to operate than NG here in Michigan. But speaking of the big beast in the basement, have you seen this thing from Dettson.

http://www.dettson.com/products/chinook-compact/

I was introduced to it at a great conference Habitat puts on here. I haven't ever worked with one but I feel like it's the only gas furnace I would consider personally, especially the Zender style duct system (watch the video). Anyone have experience or opinions to share?


17.
Feb 11, 2018 2:20 PM ET

Edited Feb 11, 2018 2:21 PM ET.

Response to Andy Kosick
by Martin Holladay

Andy,
Last week, I heard John Straube give a presentation at a conference in Burlington, Vermont. Straube mentioned the Dettson Chinook 15,000 Btu/h furnace, saying something along the lines of, "After begging furnace manufacturers for years to make a right-sized furnace, one is finally available."

The furnace is manufactured a short drive from my house:
Dettson Industries Inc.
3400 Boulevard Industriel
Sherbrooke, Quebec J1L 1V8
Canada
Tel: 819-346-8493 / 800-567-2733


18.
Feb 13, 2018 1:55 PM ET

Dettson
by Reid Baldwin

I gave serious consideration to using a Dettson system in my home near Flint, MI. From a technical standpoint, it seemed superior to what I ended up with. Business concerns stopped me from using one. No local contractors have any experience with it. I would have had to procure it myself and then have a local contractor install it based on written instructions. The HVAC contractor already hated me for making them learn how to install an ERV.


19.
Feb 13, 2018 2:05 PM ET

Stay tuned
by Martin Holladay

I'm in the process of writing an article about the Dettson Chinook furnace. I had an extended conversation with one of the company's engineers this morning, and the article should be published on GBA soon.


20.
Feb 14, 2018 11:06 AM ET

Wasted floor area
by David Baerg

The best way to make a house green is to reduce its size. So, anything that wastes floor space should go. You mentioned the big master bath with the Jacuzzi and the double height foyer.

Walk in closets are my favorite space waster. The area in the middle of the closet is only used when you are picking out or hanging your clothes. On the other hand, having one long closet along one wall of the master bedroom makes better use of that space.

En suite bathrooms are another wasted space. But I think I'm tilting at a windmill there.


21.
Feb 20, 2018 8:22 AM ET

Response to David Baerg
by James Morgan

I have to disagree about walk in closets. At the expense of the small walkway between hanging spaces they offer vastly more efficient storage space, allowing easy access to upper walls etc. Wall length reach in closets take up valuable wall space and impede secondary furnishing of a compact bedroom. Plus, if you live in a tornado or hurricane prone area they provide a vastly more comfortable storm shelter than a bathroom. For smaller bedrooms with lesser storage needs we have planned compact corner closets which provide excellent flexibility in use while taking hardly any wall space.


22.
Feb 20, 2018 8:47 AM ET

Crawl spaces
by James Morgan

Martin Holladay is an inestimably valuable source of information and good sense about all things green in building but I am afraid he betrays his regional bias in his ongoing campaign against crawl spaces. Many millions of Americans live in places where basements are impractical, and those of us whose business includes extending the useful life of older buildings groan when confronted with the inflexibility of a slab foundation. All well and good if a home is well planned from the get go but we all know that so many are not, and sadly this includes many of the 'green' home plans posted here on GBA for review. Particularly if you live south of the Mason Dixon line where access to stable subsurface soil temperatures is your friend, properly detailed encapsulated crawl spaces are one of the most important green tech construction advances of the last two decades.


23.
Feb 20, 2018 9:01 AM ET

Edited Feb 20, 2018 9:11 AM ET.

Response to James Morgan
by Martin Holladay

James,
Believe it or not, when the backhoe comes to your site to dig your crawl space foundation, you can ask the backhoe operator to dig just a few feet deeper to create a basement. This switch from a crawl space to a basement is possible at 90% of all sites where crawl spaces are installed, even though builders in North Carolina mysteriously insist that it's impossible to dig any deeper.

You'll pay a little more for a basement than a crawl space -- but a better house costs more than a not-so-good house.

And if the budget is tight, a dry slab beats a damp crawl space.

All of that said, I am being maligned. In the article on this page, while I did express my opinion that either a basement foundation or a slab is preferable to a crawl space, I didn't say that a crawl space won't work. I simply advised readers to avoid vented crawl spaces. I also advised any readers who are planning to build a crawl space to make sure that the crawl space is unvented.


24.
Feb 20, 2018 11:49 AM ET

Crawlspaces
by Malcolm Taylor

Ah - the wicked Mr Holladay is back with his nefarious campaign to malign crawlspaces.

Basements necessitate deeper excavations, our code demands engineered reinforcement for their taller concrete walls, they yield poor living-spacesand take away space on the floor above for stairs, are more prone to water infiltration, even when unfinished are more difficult to renovate or alter as their services run under the slab not through the middle as they do in crawlspaces, are more expensive to construct and more difficult on rocky terrain, require that the drains leave the building at a much lower elevation often necessitating sumps or pumping, make teenagers who spend time in them anti-social and facilitate drug abuse.

Long live (unvented) crawlspaces.


25.
Feb 20, 2018 12:49 PM ET

Response to Malcolm Taylor
by Martin Holladay

Malcolm,
Because of the tell-tale odor, you have to go outdoors to smoke pot. Basements are for teenage sex, not teenage drug use.


26.
Feb 20, 2018 10:12 PM ET

Martin
by Malcolm Taylor

I stand corrected


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