7 votes

Insulation only provides short-term reduction in household gas consumption

7 comments

  1. [7]
    skybrian
    (edited )
    Link
    From the article: [...] [...] [...] (A "conservatory" is apparently what's called a sun room in the US.)

    From the article:

    Insulating the lofts and cavity walls of existing UK housing stock only reduces gas consumption for the first year or two, with all energy savings vanishing by the fourth year after a retrofit, according to research from policy experts at the University of Cambridge.

    The latest study is the first to track in detail household gas use across England and Wales for at least five years both before and after insulation installation.

    [...]

    Researchers behind the study, published in the journal Energy Economics, say it is extremely difficult to identify specific causes of the 'rebound effect' they found, but behaviours such as turning up the heating, opening windows in stuffy rooms or building extensions may all contribute.

    [...]

    “Households in more deprived areas often have to limit energy use, so any savings created by home insulation can quickly get redirected into keeping a house warmer for longer,” said Penasco

    “This is a good outcome if policies are aimed at reducing fuel poverty in low-income households, but will not help with the UK’s emissions reductions targets or reliance on gas.” In fact, when it came to household income, those in the bottom 20% increased gas consumption straight after insulation.

    [...]

    *Conservatories are one of the most popular home improvements in the UK. Data from 2011 suggests that almost 20% of households in England had some form of conservatory, and 80% of those had some form of heating.

    (A "conservatory" is apparently what's called a sun room in the US.)

    2 votes
    1. [6]
      vord
      Link Parent
      To expand on that in particular... I'd bet a nickle most retrofits don't consider insuring a new method to provide fresh air to the home after insulating and sealing off cracks. Turns out people...

      behaviours such as turning up the heating, opening windows in stuffy rooms

      To expand on that in particular... I'd bet a nickle most retrofits don't consider insuring a new method to provide fresh air to the home after insulating and sealing off cracks. Turns out people like breathing fresh air and that hermetically sealing buildings isn't a good thing if things like air quality are not factored in.

      Heavy subsidies for Heat Recovery Ventilators should help, as it should mitigate the 'stuffy' problem.

      6 votes
      1. [5]
        Akir
        Link Parent
        Generally the problem doesn't have to do anything with how 'fresh' the air is; the problem is that the air is warm and/or humid and isn't moving. From what I understand because the buildings tend...

        Generally the problem doesn't have to do anything with how 'fresh' the air is; the problem is that the air is warm and/or humid and isn't moving.

        From what I understand because the buildings tend to be very old in the UK and Europe more generally, they tend to have old style infrastructure. I would suspect part of the problem is that these houses are being heated by an old fashioned boiler with famously difficult to control radiators. Unlike central forced-air heating systems, they don't move the air, so I can understand a person feeling stuffy; it's the motion that makes air feel 'fresh' and helps make the heat even across a distance.

        At least I'm hoping that's the case; without it this whole thing doesn't make much sense to me. Maybe Brits are just crazy? I mean, they do call their sun rooms "conservatories", after all. :P

        7 votes
        1. [4]
          mat
          Link Parent
          Define "very". My house is 70-something years old which is on the older side of average - around 50% of English homes are from between 1930-1980. For context 15% are pre 1900 and 7% post-2012. As...

          the buildings tend to be very old in the UK

          Define "very". My house is 70-something years old which is on the older side of average - around 50% of English homes are from between 1930-1980. For context 15% are pre 1900 and 7% post-2012.

          As far as I understand it even very new houses use "old fashioned" boilers with radiators. Hot water heating is very common, forced air is extremely rare. Not sure I've ever seen it in a house here. I've never heard that radiators are hard to control though, even when I was a kid we had thermostatic valves on each radiator so you can set a temperature for each room. These days many houses (including mine) have smart valves so we can heat rooms individually. So I don't heat my bedroom during the day, nor my kitchen at night, that sort of thing.

          Most of my heating is done via a woodstove these days but I don't recall ever suffering from stuffiness in the past. I open the windows for a few minutes during the day even in winter to deal with humidity, but we dry all our laundry inside during the winter so damp can be an issue if we're not careful.

          I'm not sure sealing houses well causes air problems. The Passiv building standard requires very well sealed houses and none of my German friends complain about having to open windows to get fresh air.

          My personal experience relevant to post-insulation gas use is when my student house - which was freezing in the winter due to having leaky, single-glazed windows and us being poor - was (a) insulated and (b) double glazed then our gas use went up because all of a sudden it was worth running the heating because the heat would stay in the house! Prior to that we were essentially heating the garden and a small area of sky because the house was so porous to heat. Once that was fixed we didn't have to spend our time shivering under blankets and smoking to stay warm. Instead we could sit relatively comfortably and smoke instead.

          For what it's worth I'd love to replace my water heating with forced air and a heat pump but I have idea how you'd retrofit air to a house with all brick walls and big heat pumps are tens of thousands of pounds.

          Oh, and I have a sun room. It's a 3 walled room on the side of the house which is open to the garden.

          3 votes
          1. [2]
            Akir
            Link Parent
            I swear to you that I read a story about smart radiator valves coming to market about 10 years ago and heard from British people that it was a big deal. Maybe they were just messing with me?...

            I swear to you that I read a story about smart radiator valves coming to market about 10 years ago and heard from British people that it was a big deal. Maybe they were just messing with me? Either that or they became popular very quickly.

            I am surprised that water-based heating is still popular in new construction, unless it's one of those fancy systems where the heat runs through the floor. Personally I can't stand having a room with uneven temperatures heat.

            You might want to look into mini-split heat pump systems. They're designed to be placed in individual rooms so you don't need to worry about ducting for a centralized system. Nowadays they build variations where you can have one single heat pump unit provide either heating or cooling for multiple zones while still allowing them to maintain their own temperatures. They're actually relatively simple and at least here in the US you can get DIY versions which don't require you to hire an HVAC technician to install. The downside is that they tend to be slightly noisier than central systems because each room is going to have it's own unit with a fan in it.

            3 votes
            1. mat
              Link Parent
              Smart TRVs (thermostatic radiator valves) which allow for much finer time and temperature based control, via app, probably are about ten years old. They remain fairly expensive, £30-50 each, and...

              Smart TRVs (thermostatic radiator valves) which allow for much finer time and temperature based control, via app, probably are about ten years old. They remain fairly expensive, £30-50 each, and you need a central hub for them to talk to and so on. Dumb TRVs, which require no power or wifi/zigbee, and just turn the radiator on and off based on room temperature have been around for decades though. They're dirt cheap and ubiquitous.

              I've never really noticed uneven heating from radiators, unless the room is particularly drafty already - in which case I'd imagine all heating would have the same problem. Underfloor heating is definitely a thing in higher end builds but to be honest I don't like it, although I'm sure I'd get used to it, it's just a very odd sensation a little like heated seats in a car (which I have since convinced my brain are just warm, not wet!).

              I have a mini split system in my wife's garden-room/office. Don't tell anyone but I installed it myself (which saved us probably £1000) which is technically illegal due to outdated rules here about ozone-damaging refrigerants. You need an F-Gas certified engineer to do anything with heat pumps here, even though they all use safe gases these days, and often arrive pre-filled and sealed anyway! Previously her office was heated with a resistive heater and given how insane energy prices are here now (I pay 44p/kWh during the day), the heat pump will have paid for itself by the end of winter.

              The layout of my house is such that if I wanted to replace my heating with mini splits I'd need at least six of them and I'd definitely need them installed professionally and certified as such for insurance reasons. At that price and labour point (not to mention ugly boxes all over the outside of my house!) I might as well just get one big one and ditch my gas boiler entirely. There are government grants available for such things but even so it's still a five figure investment and we just dumped a load of money into solar so it's not an option for now.

              1 vote
          2. vord
            Link Parent
            Some reading on this, from a US perspective. If this is the same Passiv they talk about heat recovery ventilators.

            I'm not sure sealing houses well causes air problems. The Passiv building standard requires very well sealed houses and none of my German friends complain about having to open windows to get fresh air.

            Some reading on this, from a US perspective.

            If this is the same Passiv they talk about heat recovery ventilators.

            1 vote