GoSeigen wrote:
Your spreadsheet figures look pretty low. Can't imagine achieving close to that without fairly major insulation work throughout, but interested in where significant easy gains are to be had. Considering fitting smart thermostatic valves; there are no thermostatic valves at present. Maybe not worth it?
GS
There are no
significant easy gains to be had.
If you look at my spreadsheet figures for my own property, that is the high end of what proper
passivhaus construction would deliver, i.e. my house barely meets passivhaus levels even after the efforts I have made. Unfortunately in the UK the improvements in BREEAM building standards were nobbled by the Conservatives under Cameron in the era of "cut the green crap" when (as usual) they allowed their mates in the construction industry to overide the technical & economic recommendations of the relevant experts. So we can do much better than I am achieving, these are not really good at all.
My house is fairly typical of what can be achieved as a result of careful thoughtful but low cost work on a period property. If you do it all-in-one-go then it would be a very expensive project. If, like me, you take the approach that each time you work on an area of the house then the additional expenditure is trivial. So when I replaced the roof on the collapsing lean-to and incorporated it into the kitchen I insulated the inside of the exterior wall with 60mm insulated plasterboard, and selected triple glazing rather than double glazing. That's the difference between £8 sheets of PB or £40 sheets of IPB, so maybe £200 extra maximum. And maybe another £300 extra for the triple. Plus I dug out the floor an extra half metre and filled that with insulation as well. So that project probably cost maximum £1000 more than it would have done if I had ignored the issues of efficient & comfortable heat-light-ventilation. When I watch my neighbours up and down my street spending £40k on a typical kitchen refurb, then repeating that every 4 or 5 years, and only ever skim coating and painting, then complaining to me about the running costs of their houses after asking how I do it, then I just figure most are just plain stupid. I'll say that again: some of them come and ask me how come mine is the nicest house in the street and why it is always so warm and light, and never damp, and they can't understand how my bills are so low. Then they go away and ignore what it takes to do it right, and spend excessively on bling. And most jobbing builders and architects in the UK wilfully & repeatedly demonstrate just the same level of ignorance.
We are taking the same approach with my GF's place. The result is decreasing costs (17% or 32% down so far) and increasing comfort, plus increased market value. The additional cost of each project is really trivial, much the same sums as I have given above. That is provided the work is done at the same time as other work in the corresponding area, and provided it is accurately specified in the scope-of-work and/or drawings. There is one exception to this, which is what it costs to do double glazing that the listed buildings people can live with, and there she uses Mettherm (
http://www.metthermwindows.co.uk/page/windows) who do not come cheap. But that is a listed buildings issue, not really an insulation issue.
In respect of your place you either have to start tackling the insulation, or you are wasting a lot of your time & money & effort. For example putting in thermostatic valves (either dumb or smart) will just result in them cranking fully open and pouring warmth through the cold uninsulated walls. You have to tackle all six sides of the house, including the floor, if you are to get your heating cost under control. But looking at the figures there is an issue with your electric consumption you need to first understand, then secondly address. You are using about as much electric (12,500 kWh/yr) in your 250m2 house as my girlfriend was in 2014 in her pre-upgrade house of 418m2, i.e. 14,000 kWh/yr. I know that at that time she had electric underfloor heating in one area and that it was cranked to max a lot of the time by the occupants of that area, and was a financial disaster. Yet your usage is even more profligate than that was, so there is something you should consider. In the case of my GF's place, early in our relationship, she put in that elec underfloor heating (and electric hot water) at the insistence of an architect and against my (gentle) advice. She subsequently realised that I had been correct, and we installed a second oil-fired boiler (7kW I think) that now feeds these loads, and removed the heating fuses, and the result speaks for itself in the data. The detail of how best to tackle each issue is case-dependent and feel free to describe the situation and ask for advice. I could write war and peace on each of the projects we have done, but unless you are prepared to go down a similar pathway that may not help you. You first have to identify the root causes of your consumption in a data-driven way, just as with any other encounter with mother nature. Keeping long term records will help you greatly with this. Given your investing etc activity I think this will be easy for you.
For my house my target (excluding FIT income, which distorts things) is to get below £3.00/m2/yr (now £5.03), and for my GF's the target is to get below £5.00/m2/yr (now £7.26) in the next cycle of improvements. That will probably take us 3-4 years as we address various areas. For example I want to finish my bathroom upgrade, which will include insulating its exterior wall, but first I have an old sailing yacht that needs the cash !
I appreciate that you are a tenant, and this may well mean an interesting conversation with your landlord, and may not be worth it. Good luck & don't hesitate to ask on any specific items (or anybody else out there).
regards, dspp