I’ve seen it hundreds of times: two houses, same price, very different energy profiles. Home design, site, orientation, and its current structure dramatically affect current energy costs. These factors can also dramatically affect comfort and plans you may have to utilize the sun or the cost to make other improvements to make that house more energy efficient in the future. It would be nice if this wasn’t so, but unfortunately it is.
As a home buyer, you have a unique opportunity to buy something that either is much more energy efficient now or something that can be economically made a lot more energy efficient in the future. You also have the opportunity to miss this aspect when evaluating homes and fall victim to buying a house where comfort may be compromised and energy costs will be a significant and growing, long-term burden.
A pre-sale home energy audit, by an independent energy auditor, is your best tool to understand how energy efficient the house you are looking at is, and what energy conservation opportunities the house may offer. The assessment should start by understanding your current objectives, future plans, budget and timeframe, and then look at prospective buildings’ energy status and prospects. Some houses are good or can economically be made good; some houses might be good for one plan but not for another. From an energy perspective, some houses are just plain bad. Certainly energy considerations should be an important purchase decision criteria.
This discussion is primarily about heating energy because it is typically the larger portion of the bill and more dependent on the house versus the inhabitants. Here are some points to consider and reasoning behind the scene:
First, don’t rely on the energy usage in the listing. Assuming the fuel usage is stated and reported accurately, there is a major factor that may make past fuel usage misleading relative to the inherent energy efficiency of the house – the inhabitants. For example: the thermostat may have been set unusually low (pre-sales strategy? or lifestyle preference?); one house uses electric for cooking and hot water, the other uses the heating fuel (be sure you are comparing apples to apples); there might be just one or two people in the house or a half-dozen (more clothes washing/drying, showers, cooking, etc.); maybe clothes are dried on a linear solar dehydrator (aka, clothes line); everybody has the same schedule or very different schedules (heat up all day or just in the evening); ages and “occupations” (number of showers, temperature sensitivity, etc.); finally, there might have been a lot or a little winter travel away from home. The only way to determine what the heating costs for a given home “should be” or “will be” is to carefully model the home “As Is,” with thermostat settings based on your lifestyle.
OK, let’s move to the next level. Assume you know that two or more houses have the same energy costs under similar conditions. Do you know what you need to know? Are the houses equal – do they present the same energy opportunities? Not necessarily…
Heating fuel usage is a function of three additional factors (beyond the inhabitants): conductive insulation of the shell, air infiltration of the shell, and the efficiency of the heating system. Improve any of these and you reduce fuel usage. The issue here is more about what can be done and at what cost, rather than what currently is. Let’s see how each of these factors can affect your plans.
Let’s assume you are looking to buy an energy dog and make significant improvements. Two houses can have the same poor shell insulation factor but offer vastly different opportunities. The worst case might be two older homes, one with no insulation in the wall cavities and other with bricks in the walls. Yes they used to build houses with bricks in the wall. Well, dense packing the empty cavities is very cost effective; but there is really no cost effective way to address the bricks, unless you are planning a complete interior gutting and renovation.
A more common situation might be where one house looses a lot of heat energy to infiltration that can be quite easily remedied in one home versus another that was built in sections over the years or with tongue and groove paneling or ceiling, or other difficult to air seal construction techniques. A third example is where all the easy stuff has been done to one house and the other house has had the expensive stuff done – amount and cost of future improvements would be quite different. Maybe one house is unable to improve further, where another house is just begging for more improvements. The bottom line is that what can be done and the costs can vary significantly. Before buying, one or the other, make a plan and get rough estimates – don’t assume that two house with the same energy costs now, will have the same opportunities or costs for improvement.
Solar opportunity is another area that should be considered; long-term using the sun should be part of everyone’s plan. There are many ways to use the sun – passive and/or active space heating, domestic hot water, and photovoltaic electric are the basics. House layout, orientation, building site, and solar access can make or break these plans. Funny, very little is factored into the sales price based on solar opportunity. Sometimes a “sunny” breakfast nook is mentioned, but the sun can offer far more than this.
Comfort is another important consideration. House design can severely impact current and/or future comfort opportunities. Slabs on grade without insulation are very difficult to remedy. Vaulted ceilings make keeping the warm air down, where you are, a challenge. A huge open layout is more expensive to heat than a smaller one, especially if there is just one person using the space most of the day. Being able to close off rooms, when not in use during the winter, allows more heat to be where it is appreciated. A family room with a pellet stove can be great for family and energy conservation. A door at the bottom of the stairs, when upstair heat is not needed, is very cost effective. Zoning, hot air or hot water heat, can be effective. A solar gain in the Active Area during the day is very comfortable and cost effective. There are many details to consider; project yourself and the house to winter conditions and activities, and then see if the house that looks great in the summer passes your “whole-year energy test.”
The bottom line is that for every $1 decrease in annual energy costs, the market value of a home should increase by $20, according to a study published in the Appraisal Journal. Thus, if a house costs $500 per year less to heat, that home should be worth $10,000 more than a similar home. And, I expect this spread will increase, as energy costs increase and the public becomes more aware of the burden fuel bills can be. In these times it pays to consider heating costs and comfort before committing yourself to 20 or 30 years of mortgage payments. A home inspection is important, but so is a pre-sale home energy audit. After all, every house is different and only a careful examination can identify the energy issues and opportunities. Remember, when it comes to buying a home, energy matters!
Dan Gibson is the Reporter and Chief Coordinator of Our Energy Independence Community (www.OEIC.us). Previously he was a participating contractor in NYSERDA’s Home Performance program and a rater in the New York ENERGY STAR Home program. He is currently building a 100% Solar Home. He can be reached at DanG@OEIC.us