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Green Building News

Minneapolis May Require Energy Evaluations on Homes for Sale

City leaders may require a blower door test and a check of insulation when houses are sold

City officials backing the energy evaluations see it as part of a plan to reduce greenhouse gas emissions. But some Minneapolis real estate agents express concerns that required energy evaluations would be invasive and impact sales. (Image credit: Robin Amer / CC BY-NC-ND / Flickr)

In Minneapolis, the City Council is tinkering with a proposal that would require an independent energy evaluation of houses when they go on the market.

Although the plan is still evolving, according to an article posted by the Star Tribune, evaluators may be boring holes into walls of houses built before 1980 to check on insulation, and conducting blower door tests to find out how leaky the building envelope is.

The new requirement would go into effect next year, but the exact language of the proposal has yet to be released. That’s on the schedule for a City Council meeting at the end of the month.

“The city really wants to make some headway in terms of fossil-fuel emissions,” Councilor Cam Gordon told the newspaper. “And with our cold winters … I think that the energy that goes into heating homes is a major contributor.”

The new requirements would become part of the Truth in Sale of Housing evaluation that is now performed on all houses sold in Minneapolis.

An exploratory hole bored into a wall would allow an inspector to see how much insulation had been installed. A blower door test calculates airtightness by measuring the amount of air that leaks into a house while it’s under negative pressure.

The amount of insulation in the walls and roof, and airtightness both are standard metrics in new house construction. It’s not yet clear how the information would be bundled into a report or scorecard useful to potential home buyers.

In a report for the city, the Center for Energy and Environment (CEE) described energy evaluations that are now required in several U.S. cities, and said residential energy disclosures would “unleash market forces” that would improve energy efficiency. CEE also mocked up a sample “Home Inspection Energy Report” that might be used in Minneapolis.

“By providing a simple and transparent way to assess efficiency, energy disclosure can help buyers be more sophisticated in their home search, encourage owners to invest in efficiency, and help sellers recoup the value of the efficiency investments they have made,” the report notes.

An estimated 90% of all single-family homes in Minneapolis were built before 1960, the report says, before a residential energy code requiring minimum levels of insulation and other efficiency features had been been adopted. The authors estimated that energy upgrades could save city residents $8 million a year and would have a simple payback of 10 years in savings alone.

The backdrop to the proposal is the city’s Climate Action Plan, which seeks to make whole-house efficiency upgrades to 75% of Minneapolis homeowners by 2025. A pilot program set out to upgrade 500 homes per year in 2015 and 2016.

The report makes these other points:

  • A disclosure of energy bills would be less expensive than an audit of energy “assets” but ultimately would not be as useful.
  • Homeowners are more likely to make upgrades soon after the purchase, so energy disclosures at the time of sale are effective in encouraging improvements.
  • Knowing that efficiency will be disclosed at the time of sale motivates homeowners to complete energy upgrades early on so they will build in the best resale value.

Energy disclosure policies are already in place in a number of U.S. cities, including Austin, Texas, Berkeley, California, Chicago, and Portland, Oregon.

Real estate agents don’t like it

The plan isn’t proving very popular with real estate brokers, according to the Star Tribune.

“Although I’m all for energy improvements, why does the city of Minneapolis feel they have the right to invade the sanctity of my walls,” said Stephanie Gruver of the Re/Max Results agency. “Cutting a 2-inch hole in my 1928 hand-plastered walls is going way too far.”

Other brokers and real estate evaluators said the new requirements could more than double the cost of a Truth in Sale of Housing report, now at about $200.

Eric Myers, the director of government affairs for the Minneapolis Realtors’ association, was concerted about the financial impact on buyers and sellers. Those fears were echoed by Shae Hanson, a real estate agent.

“It’s going to be negatively impacting the real estate transaction between a buyer and seller,” Hanson said, “potentially putting Minneapolis homes specifically at a disadvantage.”

Mike Moser, an independent evaluator who compiles TISH reports, said blower door tests would take longer than the city expects. He also was concerned of potential liability should an evaluator hit a wire when they drill into a wall, according to the Star Tribune.


  1. tommay | | #1

    I think there should be an evaluation and efficiency test on the council first....

  2. user-723121 | | #2

    "A disclosure of energy bills would be less expensive than an audit of energy “assets” but ultimately would not be as useful."

    I disagree.

    Previous energy bills for a residence can tell you about all you need to know regarding a building's efficiency. Couple this with a blower door test, some building element sizing and it becomes quite easy to fill in the blanks. The vintage of the house will lend information as to the typical insulation used for that period. There may be upgrades to attic insulation that are visible through the attic access. I always start an energy upgrade with previous energy bills and a blower door test. Improvements to the structure are measured the same way, the monitoring of energy bills and a follow up pressure test.

    We can't know the owners lifestyle habits, thermostat setpoints and the like, but previous energy bills will give a good idea of building efficiency.

    1. Expert Member
      MALCOLM TAYLOR | | #4

      That's a tough one. People's everyday behaviour varies in surprising ways. The owners of the last house I built cook almost every meal on their barbecue, he showers at the gym, they use their wood stove religiously for all their heat without ever turning on the baseboard back-up, and at the same time keep two good sized windows open. I think any prospective buyer would get a really deceptive idea of building's efficiency from their past bills.

  3. leenewton | | #3

    We are becoming a society dependent on someone else doing everything for us...this is a bad move in my opinion.

  4. onslow | | #5

    The nanny-state strikes again. Well intentioned, but severely misguided. People buy neighborhoods, school districts, and commuting over energy efficiency. Witness the many horrible energy pigs built for the last 40 years. Almost all in "new" areas serving new industry and businesses. For added overreach, throw in income displacement of housing options, extinct technology job bases and the general social biases of people. Then mix in politicians and activists for a nice agitated froth. Housing stocks will have value accordingly.

    It is critical to note that the article states that 90% of the housing stock is pre-1960. The last date for sale of lead paint I believe was around 1972. And of course nobody used asbestos in any of the houses built prior to 1960, right? So the brilliant CEE people will propose coming to 90% plus of homes to expose either an lead paint issue or an asbestos hazard. Genius! Now all they need to find are approximately 300,000 hipsters willing to gut renovate the entire housing stock and all is good. Market forces of course will draw them like flies and maybe then the people who actually do the work will be able to afford to do the tens of thousands of dollars upgrades needed to stay in their own current homes. They can cash out when hipsters arrive demanding to buy in the new paradise of Minneapolis, happy to know that they meet the new standards.

    For years in Illinois it was allowed for anyone to call the (then two) gas companies, and find out gas bills for a property. Somewhat illuminating, but largely useless for determining how well a house performed.

    As Malcom notes, user habits could easily distort energy records. It was generally known among young renters that finding an apartment above an elderly couple could be golden. You got radiant floor heat.

    I may have a dis-peptic view of peoples actions, but I suspect 98% of people will choose to do the very least they can. A booming industry in scams will surely flower.

  5. user-723121 | | #6

    To say there is no relation to a building's energy use and it's energy efficiency is just not true. I am for a modified version of the proposal mentioned and not drilling homes full of holes to check for insulation.

    For those interested I will explain why gas meter readings are of value to me when determining the relative energy efficiency of a building. It is much like checking the gas mileage for your car. The number of miles driven divided by the gallons used. This will vary from tank full to tank full, season to season but the aggregate is the gas mileage for your car. How else could it be accurately measured? Manufacturer's estimated MPG?

    Gas meter readings for a residence can be used in many ways. The annual energy costs for the building will be known for budget considerations. The return on investment for an energy efficiency upgrade can be calculated.

    I use gas meter readings this way. Read the gas meter the first of every month throughout the year. The non heating use in MN (hot water, cooking, etc.) will be in the months of June, July and August. The total of these months divided by 3 is your monthly gas usage for non heating. The gas meter readings for the heating season will be less the summer monthly usage for heating energy calculation purposes.

    I will include in my calculations the monthly gas used in therms, the square footage of the conditioned space and the heating degree days (hdd) for the month. Now I can arrive at a number that is very useful in comparing homes and for considering energy retrofits, Btu's per square foot per heating degree day (Btu/sf/hdd). In reading gas meters for 35 years for new homes I have built and retrofit projects undertaken this number is amazingly consistent year to year. Monthly Btu/sf/hdd will vary slightly due to the solar fraction and deep earth seasonal buffering.

    Our house is running right at 2.3 Btu/sf/hdd for the last 12 years, neighboring homes around 5, all built at the same time. For our house, air sealing, a 95% furnace, R-100 attic and an efficient configuration make a big difference. 3 story walkouts with tuck under garages will never come close to the potential efficiency of a rectangular rambler with good solar access.

    1. Expert Member
      MALCOLM TAYLOR | | #7

      "To say there is no relation to a building's energy use and it's energy efficiency is just not true"


      Hopefully no one is saying that. I sure am not. It's just it can paint a very incomplete picture. Your two examples illustrate that.

      Dividing the miles driven by a car by the gas used leaves out important variables like whether the driving was done on highways, or all within the confines of urban areas with their attendant traffic jams. The two would yield wildly different results.

      Your own monitoring of home energy consumption is all within the context of one user. I don't think you can assume someone who bought your home would have the same bills.

      The reason ignoring occupant behaviour in these sorts of standards matters is there have been various proposals, like having builders guarantee certain levels of energy efficiency for their work, which might penalize them for not achieving the minimums, when in fact the poor results as measured by the occupant's bills, might have had very little to do with the efficiency of the building.

  6. user-723121 | | #8


    I respect your opinion and always have. I do understand occupant behavior is an unknown and qualified that in my first post. I have found in my energy monitoring, occupant behavior to be quite similar, 70 degree winter setpoint and the like. How do you measure energy efficiency for a building if you do not use actual energy metering? I personally can't think of another way.

    1. Expert Member
      MALCOLM TAYLOR | | #9

      I don't know. Perhaps that's the problem. In an ideal world I guess we could shunt the owners out to a hotel for a month, or in the case of new construction monitor energy use before occupancy.

      In the absence of simple way of ascertaining useful data on efficiency, the Minneapolis initiative may be fairly useless.

      BTW, I enjoy your posts and find them both interesting and useful.

  7. user-723121 | | #10

    You may on to something Malcolm. There can be a period where a house is unoccupied and the gas usage for that period with normal thermostat settings should be quite accurate in determining heating efficiency, The hot water heater could be set on pilot.
    In my building and monitoring of 5 superinsulated homes in the 1980's I found energy use for heating to be very similar between the 5 homes. They were all built to identical specifications, two story with attached garages and had very similar ACH50 of around 1.25. The one difference I could see was the 2 homes with the better Southern exposure (East/West long axis) performed slightly better than those with a North/South axis.
    2 identical homes were built in Canada a number of years ago, left unoccupied for testing purposes and I can't quite remember what tests they did. It may have been for a thermostat setback vs non setback evaluation or to test heating appliances of different efficiency, maybe someone can chime in on this. It also may have been to see if 2 identically built homes performed nearly the same. A lot of great information has come out of Canada over the years on building energy efficient housing.. I had the distinction of meeting Harold Orr at the 2007 Passive House Conference. He gave a slide show on his projects for those interested one evening and it was fabulous.

    1. Expert Member
      MALCOLM TAYLOR | | #11

      I think Canada provides a pretty good model for how government can make a difference to housing. Relatively early they took research seriously, sponsoring a lot of the seminal studies, and funded buildings that advanced energy efficiency. As a young inexperienced architect working in the late '80s, it was great to be able to call the NRC or CMHC and get free detailed advice from scientists on any number of topics.

    2. tommay | | #15

      Doug, yes, every home will be different even if identically built. Location, orientation, Internal mass and many other factors come into play. Using zones as a baseline for homes built within a zone doesn't really cut it. Take two identical houses and put one on top of Mt.Washington and the other near the base for example....two different worlds within a few miles of each other.
      Design, test and adjust is the best we can do for each individual structure.

  8. onslow | | #12

    Mr. Taylor and Mr. McEvers,

    I think Canada's building code was also behind this episode. I seem to recall that requiring plastic film on the interior of outside walls was part of the problem despite efforts to blame shoddy construction, which of course would have been necessarily overlooked by government authorities. Much as I loath Ronald Reagan and all who follow him, the phrase " I'm from the government and I am here to help" does have a particular resonance when judging the proposed legislation in Minneapolis. While a different issue is involved in these articles, it is still demonstrative of how flawed mandates (building codes) can be and how relying on the protection/enforcement of/by "authorities" is often a fiasco.

    I will try to dig into my archives and find the articles about much better Canadian efforts to apply building science. Some agency did create a series of heavily monitored sheds to get hard data on various wall construction details. Sadly, the GBA's own inquiries from our Canadian neighbors would seem to indicate that many local codes and inspectors have not been keeping up, at least in regard to plastic on walls. And yes, I do know that Martin has said many times that the plastic issue is overblown, but it seems best to use more current building science recommendations.

    I will also try to find the references I had set aside for a pair of houses built sometime around 2008 or 2010 in the United States. My memory is telling me that ORNL or a similar agency worked with a company in Tennessee to build and monitor two homes for a full year unoccupied by people. The differences in wall construction or heating choices eludes me at the moment, but the relevance is the test was being done to eliminate all variables caused by people's behaviour. This at least would settle the energy value of one home over the other. Whether people would behave any better in these houses remains an open question.

    1. Expert Member
      MALCOLM TAYLOR | | #14


      Practicing here in BC I followed the Condo Crisis, and read both official reports. While the presence of poly did to some extent contribute, because it reduced the drying capacity of the building assemblies, overwhelmingly the problem was bulk water infiltration from the exterior. If there had been no poly those building still would have failed. It's also worth noting that the same building code requirements were (and remain) in place through out the country, but the building failures were limited to a small area of the BC coast.

      While it seems clear that poly isn't always a good idea, I don't think it can be blamed for any of the premature failures we have seen in Canada, and there appears to be evidence in eastern provinces it is what has added enough resilience to walls covered with what should in theory be inadequately thick exterior foam, that they have not experienced any of the dreaded Wet Sheathing problems.

      One of the benefits of using poly during the decades before blower door testing, was that it made the vapour and air-sealing a discrete construction activity that could be inspected prior to drywalling. The quality of the work could be observed and that took the guesswork out of it. During the same period there was no alternative system, and most buildings elsewhere simply didn't do air-sealing.

      Requiring the use of poly came at a time when levels of insulation were being dramatically increased without any consideration to vapour diffusion or air leakage. There were widespread failures of housing built this way, most notably in Newfoundland, and poly solved the problem. That we have now developed better ways to deal with these issues by using other materials as barriers, or where appropriate retarders, suggests an evolution in technique, not a condemnation of something that was causing failures.

  9. onslow | | #13


    Back again briefly, these links are current for the test homes I finally found on the google.

    Now four homes for sale, all very different methods of construction.

    Also found this

    Energy analysis of homes with one (not well favored on GBA) method of construction. Be curious to know how the moisture issues have faired in these homes.

  10. onslow | | #16

    Mr. Taylor,

    My awareness of the condo failures came from readings I did about 10 years ago when I was first finding the GBA forum and educating myself about more energy efficient building techniques. Whatever sources were covering the BC condos at the time seemed to be focused on the poly air sealing, so my bad for simply accepting others opinions. If the poly wall sealing was not the major cause of the failures as you state, then this only amplifies the point I was attempting to make regarding the not very well thought out legislation proposal in Minneapolis.

    If the existing code used in that area of Canada can result in 65,000 condos being that bad, then please consider the possible effects the Minneapolis proposal might have on a housing stock that represents building materials and methods used over the last 100 years. The correct method of improving energy efficiency in meaningful ways for each home will probably require an great deal more thought and consideration than will be available or achievable. If inspectors couldn't manage to identify shoddy construction in 65,000 cases, will the inspectors in MN be able to inspect energy retrofits with any better record.

    One of the articles I linked to seems to indicate that while some people got assistance, many did not and the money ran out eventually anyway. Comments at the end of the article suggest unscrupulous real estate people seem to be failing their customers by not disclosing risky units. It would seem the local government agencies are also sidestepping the issue, unless they have sought to condemn buildings or at least block sales until the matters are corrected by the builders.

    In any case, my main contention is that, as laudable as the goal may be, bludgeoning people into improving energy efficiency can, and most likely will, result in many unintended consequences. Some buildings may develop moisture issues, housing availability to people with modest incomes and renters will certainly be affected. A low value property will become even less valuable if the owner can't upgrade. A landlord will have to raise rent if forced into costly retrofitting. Marginal value housing stock may become prey to economic red-lining creating slums or alternatively targets for gentrification. I just remain unconvinced that the net savings of fuel use is justifiable given the potential for serious disruptions on so many levels.

    1. Expert Member
      MALCOLM TAYLOR | | #18


      i'm not sure what the implications of the Condo Crisis are for proposals like those in Minneapolis , but we now don't have a problem with building envelopes in BC, and the three main reasons for that are:

      - Making professionals responsible for ensuring the building envelope is properly designed and executed. A "Professional of Record" must sign off on every permit.

      - Changes in the building code that require much more robust assemblies.

      - New inspections of the building envelope to ensure compliance.

      These so far appear to have worked extremely well.

  11. user-723121 | | #17

    Sooner or later we must take responsibility for our individual energy usage. If fossil energy can be saved by making upgrades to existing housing with a favorable return on investment, wonderful. I did not see anywhere in the article a mandate for anyone having to upgrade their home before or after the sale. It is a citywide proposal to reduce residential energy use and a energy rating for each home at the time of sale would be part of this. If money could be provided to make energy upgrades to existing homes with a favorable return on investment, I can't find fault in that.

    A blower door test, infrared scan and a years worth of gas and electric bills would be the start of a well grounded energy evaluation for a residence. The diagnostic equipment today is unbelievable and in the hands of skilled energy raters is something to see. Anyone who is contemplating buying a home and making the investment required deserves to know all they can about the homes they are considering. This will make for a stronger community and start a discussion on individual carbon usage that is long overdue.

  12. onslow | | #19


    I admit I have failed to make a more clear case for my resistance to the proposed legislation. I have also misunderstood the CEE representatives comments about "market forces being unleashed" and "Knowing that efficiency will be disclosed at the time of sale motivates homeowners to complete energy upgrades early on so they will build in the best resale value." as being a forced condition before sale.

    However, I and apparently many others in the comments section of the original Star Tribune article agree with me that this proposal is not going to do much more than cost money better spent elsewhere. There is already a Truth in Sale of Housing ordinance that makes it a misdemeanor to not comply. The inspection must be completed withing 3 days of the first listing, advertising or sign placed. The list of things subject to "visual inspection" is typical and a bit laughable knowing how many bathrooms and whatnot I have had to repair after "home inspectors" gave a clean bill of health. One of my personal faves was saving a friend from putting in an offer on a house that had been fully inspected and approved. The attic was absolutely chock full of black mold due to bathrooms venting into the attic. All I did was pull down the access ladder and look.

    The notion that blower tests and holes in walls will done competently does not jibe with my past experience of paid inspectors. That is the relevant connection to the condo crisis. Supposedly competent officials all passed on the plans and execution of the buildings. Which failed massively. And by your own defense, not because of the poly airsealing. If the MN answer is to drill a hole in homes that are almost 100% likely to be under insulated and suggest stuffing more in, what is to say the results will not be much like those you mentioned in Newfoundland.

    As I noted before, each house will necessarily need much more thought and attention to details to not build in a future failure. If "market forces" get unleashed to provide quick fixes to boost selling prices, then I am of the opinion that more harm will be done than good. All with the added powers and conditions of the state.

    One comment attached to the Star article observed that it cost $150 for a permit to replace his front door. I have certainly not encountered that level of permitting control. It was further observed that maybe rebating or eliminating the permit fees for energy improvement work would be a much better approach.

    And of course, there remains the issues of lead paint and asbestos disturbance or discovery. Does the record of either's existence suddenly put a home in non-compliance with existing code? Would the home owner then be compelled to remedy the condition? Would the costs of remediation render the property valueless and subject to condemnation? These are potential side effects which create a "gun to the head" of property owners which do nothing to help with fuel use reduction.

    It also worth noting that Mr. Gordon "thinks" that heating is a major influence on emissions. Knowing the highway system surrounding Minneapolis which operates year round, he may be as ill informed as the CEE representative who could not answer whether other cities they have advised on energy issues have enacted legislation similar to that proposed in MN.

    1. exeric | | #20

      "It also worth noting that Mr. Gordon "thinks" that heating is a major influence on emissions. Knowing the highway system surrounding Minneapolis which operates year round, he may be as ill informed as the CEE representative who could not answer whether other cities they have advised on energy issues have enacted legislation similar to that proposed in MN."

      I think you tipped your hand here that you have a predetermined philosophical stance about this subject. There is no debate that heating homes, in any form that its done, increases emissions with the predominant current sources of energy, be it electrical or through the burning of fossil fuels. If you deny that, or try to mitigate it, by using the excuse of emissions from vehicles being worse I would say you've just ruined your credibility. I am now thinking you may be an anti-government libertarian that molds their "facts" to that radical preexisting antigovernment view. Those types of people seem to always come up with the argument that something can't be done to improve a situation if there remain other situations that are still bad. It's as if all things that need improvement have to be done simultaneously or else nothing should be done. That's just a libertarian anti-government excuse that always eventually comes out when the argument is being lost.

  13. JC72 | | #21

    I'm not a fan of this proposed "solution" when dissolving the local utilities commission is a much more efficient means of reducing power consumption.

  14. user-349933 | | #22

    It looks like Minneapolis has created a perfect storm. First they removed zoning restrictions to allow multi-family housing in residential neighborhoods. Then they require energy evaluations on homes prior to selling them which will drive down the price of the older homes. This will increase the number of tear downs available while lowering the costs to the developers. Then new multi-family homes can be built in neighborhoods where only single family homes were allowed. The payoff will be higher property taxes on the new multi-family homes going back to the government to fund commissions.
    Will a smaller older home get a lower score then a new home that is twice as big that actually uses more energy? Do McMansions get a size penalty or are homes scored strictly on how much insulation they have and the results of the blower door test? I think utility bills are a better judge of energy usage then what is being proposed.

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