Efficiency / DIY / cost-saving projects.

Soldato
Joined
18 Oct 2002
Posts
6,669
I'm an eternal tinkerer / optimiser and I'm itching for a new project, but I have a feeling that there is little else I can do to the house.

Quick sitrep:

  • Small (100 sq m) 3-bed detached house, built 1985.
  • ~5 year old condensing combi gas boiler.
  • Original double-glazing.
  • Cavity walls with millions of styrofoam balls inside!
  • Loft conversion with skylights.
  • Eaves in the loft have ~7cm (2.5") of mineral wool insulation.
  • Electricity and gas averages £34 per month each.
  • Current efficiency rating is C71. Potential is B85. (average for NI Is D60!)
Since moving in 2 years ago, here's what I've done so far:

  • Replace all bulbs with LEDs.
  • Install better bathroom extraction fan with backflow valve.
  • Bled radiators & checked magnetic filter.
  • Optimised boiler temperature to ensure return temp is as low as possible for condensing efficiency.
  • Installed fans in the two downstairs radiator boxes to aid the rooms heating up (and therefore reduce return temp).
  • Checked and fitted backflow valve to kitchen extractor fan.
  • Checked and blocked any gaps in the windows / doors for drafts.
  • Checked the fridge & freezer are at the correct temperature.

Here's all I can currently think of:

  • Install cleaning and anti-corrosion solution to the central heating.
  • Install a small solar panel on the shed. Just to tinker with - it won't be connected to the mains (yet). (This kills two birds with one stone as the roof leaks a little, so I can get a new toy and fix the leak!).
  • Add spacers and more insulation to the eaves. I know that the current insulation of only 7cm is pretty poor. However, adding spacers and more insulation will raise the height of the "floor" and therefore reduce our storage space. Given that the eaves "only" cover about 1/3 - 1/2 the total floor area (because of the loft conversion), I'm loathed to do this.
  • Replace the radiators with newer, more efficient ones. Again, I doubt I'll (ever?) do this due to the cost.
  • Ensure we're on the cheapest tarrifs.
  • We need a new bathroom and I plan to change the electric shower to one that's fed by the combi boiler. I suspect this will improve the pressure of the shower and also be cheaper to run (I'm pretty sure heating water via gas is cheaper than electric).
  • Install weather-compensation for the boiler. From what I can tell, this probably isn't worth it? I'm *guessing* that cost would be ~£250 for the unit and ~£250 installation and the savings would be ~10% (~£40 per year). Probably not worth it.

Here's what the energy report suggests we could do (too expensive until PV comes down in price!):

  • Solid floor / floor insulation = £5k, potentially saving £50 pa
  • Solar water heating = £5k, potentially saving £30 pa
  • Solar panels = £7k, potentially saving £270 pa
I'm guessing there isn't anything else "tinkery" that I can do, but if you have any weird and wonderful ideas, let me know!

:D:cool::p
 
Soldato
Joined
9 Mar 2003
Posts
14,056
Putting in insulation and lowering leaks (without causing damp) is the most effective way of reducing bills. Outside of generally just using less of course.

If you don’t want to add more rock wool you could replace it with better insulation. Don’t forget all of your internal stud walls either. If your ripping out a bathroom it’s well worth getting insulated boards like marmox to sit behind the tiles.

Windows are typically a huge source of heat loss. Make sure all the seals are good and the windows actually close on to them properly. A poorly aligned UPVC window will leak a ton of heat but people tend to ignore them because they have double glazing.

I doubt any of the other things on your to do list will save you any money at all. By all means so it if your ripping stuff out as an upgrade but not with the expectation of saving cash.
 
Associate
Joined
8 Mar 2006
Posts
1,402
Location
York
I have done a similar thing with our 70's semi.

I topped up the insulation to 300mm ( I just used the 200mm top up stuff over the old stuff.)

We replaced the 10+ year old leaky combi with a new Worcester A rated one. The old Voikera boiler was a D rated one when new, but leaked and lost pressure so much have been much worse in reality!

The house had loads of halogen and non energy saving bulbs when we moved in. In total I replaced 42 bulbs/fittings and saved 1626.5watts which I'm pretty pleased with.

We have had a new front door fitted with no letter box (composite one, so better insulated/sealed and no draft from the letter box).

Our electric bill is fairly low as I did the LED's a few years ago, but our gas has always been really high in the winter. The boiler was fitted in Feb so I'm hoping to see a massive reduction in our gas bills this winter. We have also replaced our old crappy gas oven with a new and hopefully efficient electric one, so that should hopefully bring the gas usage down even further.

I'm not sure what else to do really? I think with older houses you can only go so far in terms of efficiency before it gets expensive and is no longer cost effective.

Dave
 
Don
Joined
19 May 2012
Posts
17,050
Location
Spalding, Lincolnshire
Air Source Heat Pump (or Ground Source Heat Pump) is about the only other thing possibly worth consideration. We moved from a coal fire/backboiler setup to ASHP just over a year ago, and through winter noticed a considerable saving.

Whilst the saving vs Gas is likely to be less (especially versus installation costs, unless you can get a grant or similar), if you are looking at renewables (solar, wind) in the future, potentially they can generate the electric needed to run an ASHP.
 
Soldato
Joined
9 Mar 2003
Posts
14,056
I doubt you’ll save any money going G/ASHP VS a modern Combi gas boiler, even if you were at the point of replacing the existing gas boiler. Gas is just too cheap at the moment to make any savings from a purely economic argument.

If you are planning a decent sized solar install then that may look different.
 
Soldato
OP
Joined
18 Oct 2002
Posts
6,669
I have done a similar thing with our 70's semi.

I topped up the insulation to 300mm ( I just used the 200mm top up stuff over the old stuff.)

We replaced the 10+ year old leaky combi with a new Worcester A rated one. The old Voikera boiler was a D rated one when new, but leaked and lost pressure so much have been much worse in reality!

The house had loads of halogen and non energy saving bulbs when we moved in. In total I replaced 42 bulbs/fittings and saved 1626.5watts which I'm pretty pleased with.

We have had a new front door fitted with no letter box (composite one, so better insulated/sealed and no draft from the letter box).

Our electric bill is fairly low as I did the LED's a few years ago, but our gas has always been really high in the winter. The boiler was fitted in Feb so I'm hoping to see a massive reduction in our gas bills this winter. We have also replaced our old crappy gas oven with a new and hopefully efficient electric one, so that should hopefully bring the gas usage down even further.

I'm not sure what else to do really? I think with older houses you can only go so far in terms of efficiency before it gets expensive and is no longer cost effective.

Dave

Cool!

Re: Gas oven - we have a gas oven as it was part of the house sale (well, a bit extra, but saved us buying a new oven when we moved in).

However, I was under the impression that a gas oven would be cheaper to run?

Having said that, on the (distant) list of things to do / upgrade would be an induction hob, so it will probably get changed eventually.

Just poured Fernox F3 into the central heating system and will leave that to slosh around for a while before changing to F1.

Then we'll practically get free heating thanks to the amazing increase in efficiency! :D :p
 
Associate
Joined
8 Mar 2006
Posts
1,402
Location
York
Cool!

Re: Gas oven - we have a gas oven as it was part of the house sale (well, a bit extra, but saved us buying a new oven when we moved in).

However, I was under the impression that a gas oven would be cheaper to run?

I'm not sure if they are cheaper? Our old gas oven specialised in food burnt on one side and raw in the middle and that would take well over the advised cooking time of anything. The switch to electric has been long overdue!

We had our heating flushed out and a filter fitted with the new boiler too, we should see the savings in winter.

We have nest home thermostat (that came with the boiler). I can't see how it's saving us money as it just means my wife can increase the temp of the heating from the sofa rather than having to walk over to it. If anything its using more energy because of this. The better timer settings are useful such having weekend and weekday settings.

Dave
 
Soldato
OP
Joined
18 Oct 2002
Posts
6,669
What about rainwater storage tank with pump for toilets and outdoor tap? And water meter of course.

Smart heating, eg Tado?

No water charges in Northern Ireland! :D

I'm not sure if they are cheaper? Our old gas oven specialised in food burnt on one side and raw in the middle and that would take well over the advised cooking time of anything. The switch to electric has been long overdue!

Yes, that's true. Pizza from frozen is "supposed" to take 15 mins, but it takes 30 mins in our gas oven, even if leaving it for 15 mins to warm up first.

That's including the fact that I've used an IR thermometer to record the oven temps at various gas marks so we know we're cooking at the right temperature (including top, middle and bottom shelves!).
 
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