Basic rules 3

Five Simple Rules For House Design That Drastically Lower Energy Costs

It is time to distinguish between the hype of “sustainability” and the essential necessity to rationalize our buildings to a changing climate. Mitigating the impact of what we build on the environment just makes sense: economically and morally. But the morality of hawking gimmicks, products and technology as a sales tool—which often cost more and cannot be recouped in any reasonable amount of time—is just false and empty marketing. 

There is nothing new in selling real estate, but right now America is in the middle of a Housing Bubble, creating a sales pitch of deafening din, promoting “sustainable” or “green” homes (with enhanced price points), virtue signaling “net-zero” or “passive” homes. It remains a open question whether these claims have any validity at all, but one thing is clear: whether it’s black window sashes or a LEED Silver rating, in this insane market the imperative of limiting our carbon use has become as useful to real estate brokers as a “designer kitchen.” 

Architect Steve Mouzon, author of The Original Green, calls this blizzard of marketing the “Gizmo Green” phenomenon, where technological fashion statements are tacked onto (too-)large homes with huge carbon footprints. An entire industry of ranking and grading systems—including LEED, WELL, fitwell, Green Globes, BREEM, and Green Star—hype their programs to the point where they become part of the marketing strategy for builders, developers, and real estate agents. Architects, in turn, use the rating systems and acronyms to prove their value to potential clients.

All of these programs—and most architects—are centered on “doing the right thing,” living lightly, using less carbon. In the end, though, these good intentions are leveraged to promote their own value (and cost). But I’m convinced that the average homeowner can do a great deal of good, and save money, with virtually no design premium and minimal building cost, if they think of some basic rules.

I am not talking about “green” aesthetics, or the religious fervor of Sustainable Commandments, such as “the greenest home is the one that’s already built/smallest/most efficient/off-the-grid” (take your pick). I’ve discovered five pragmatic, universal, approaches that can mitigate the energy use of every building, everywhere. Of course, each location needs more pointed and directed requirements, but every location benefits from these relatively simple moves. 

The situations described below are for any site, but were applied to one Connecticut house, so any “stats” used to sell equipment for any given site  are not applicable. These rules evolved from 40 years of experience and require no esoteric calculations, “rated” professionals, special technology or ratings systems, so those who earn a living providing those features may not like them, but here goes:

Here, the 2.5-foot eaves and gable roofs over doors fully protect the exterior. Roof overhangs lower maintenance costs: painting for some homes, siding and window or door replacement in others.


1. All roof eave extensions should have a minimum overhang of 1.5 feet. Both unwanted solar gain and wear and tear on wall surfaces are reduced; all openings are better protected.

The extended eaves do more than protect; they direct water away from walls and to impervious surfaces or below grade drainage, pulling water away from the foundation. Gutters in a typical home may cost $5,000–$8,000 (or more); by eliminating them, those costs (and the energy used to produce them) is saved. (Note the strategic use of gutters over mechanical equipment.)

2. If the building’s eaves are extended, the rationale for most gutters becomes almost meaningless. I propose that gutters are used to only collect water for use or to protect exterior doors and mechanical equipment as needed. Weather-generated water can be freeline dripped (by those extended eaves) to surface water control/detention systems. The cost of maintenance and carbon in the manufacture and installation of gutters is unnecessary, and their never-ending maintenance is expensive and wasteful.

Extended eaves protect windows that allow for operable glass in remote locations, minimizing HVAC use. Venting windows are minimally more expensive than fixed units ($300+/- per piece) and the installation cost is the same: when the air flows over your skin, you do not need to treat that air to reduce its temperature as much to be comfortable, thereby using less energy.

3. When the room is over 100 square feet, provide a minimum of two operable openings, remote from each other, totaling 5% of any room’s floor area. Limiting air movement increases air conditioning use. Unless generated renewably, on site, all electricity used in air treatment comes from somewhere and costs carbon emissions. If the thermostat is off longer (or there isn’t one), there is less energy used.

This 3,200-square-foot home has five HVAC zones. Four years of occupancy has educated the owners that a sixth would have been best (three for bedrooms, rather than two). Averaging 600 square feet per zone is often far more control than is offered in most homes. A heating zone can cost as little as $3,000, and as part of the necessary system there is little material used in its creation: and wherever that zone is, the overall energy use (and cost) for treating air is less.

4. Require an HVAC zone for each 600 square feet of space, limiting the conditioned air needed for places of solar gain and facilitating lower treated air in places where there is a lack of use.

This loft space reveals several rules: First, the R-48 foam insulation makes the summer heat and winter freeze controllable. The same roof cavity with traditional Fiberglas is both a fraction of thermal insulation of foam solution and the need to vent makes a weather seal harder. Additionally, a door to this space allows for a separate zone. Third, the skylight is operable, and when cracked open works with the window opposite this view to minimize the need for air conditioning.

5. A roof is the worst place in any building for thermal efficiency. Rather than complicated venting and endless gaps between the roof planes, why not require foam insulation on all roofs, everywhere? The R-values can vary, but every climate benefits from the seal and lack of heat transfer at the top of any building’s interior, whether it’s heat lost in the winter or solar gain in the summer. No matter the latitude, this one product use in this one location soon pays for its added cost.

Just these five requirements are low-tech, high-value, and aesthetically neutral, and they are basic value increases in the long-term worth and lower energy use of any building, anywhere. Many techno-devotees will hate their “dumbed down” simplicity, but these simple rules work on every building to reduce energy use and maintenance.

Why not require them?

All photos courtesy of Duo Dickinson Architects.


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