We’re now nearly two months in to living with our air source heating system and starting to look at other ways we can improve our energy use.
At long last we had our loft insulation put in, and we immediately felt the difference.
The temperature change between downstairs and upstairs has gone, and going into the loft is now a much colder process — just showing how useless the original insulation was.
A huge hat tip to Phil at LoftForce for his excellent work, which also involved part boarding the loft.
Since installation of our air source system we’ve used 1,279 kWh of energy to power it and generated 3,406 kWh of heating. Or around a 266% efficiency rating, which is a bit disappointing. But we think the poor insulation is partly to blame for that.
Our big surprise over the last weeks has been learning that we have no cavity wall insulation, despite the EPC assertions (based on the age of our house). We’re still leaking heat!
The Energy Savings Trust estimates that around 1/3rd of heat lost in an uninsulated home escapes through the walls. That’s a lot of energy wasted.
We’d had suspicions about not having the insulation after hearing mice running around in the cavity space, so we looked into how we would find out without drilling a hole in the wall (TL:DR you can’t).
We found an ally in Julie at The Warmer Group who gave me a call to explain that all cavity wall work in the UK is carried out under guarantee, so if it had been done the Cavity Insulation Guarantee Agency (yes, there really is such a thing!) would have a record. If the insulation was sub-standard, she told us, then they would look at getting the original contractor to correct it. Any work done by another contractor could invalidate the warranty, so we needed to be sure.
Back to our solicitor to check if there were any documents about the insulation (there weren’t), then off to CIGA to check for a record of the work with them (there wasn’t any), and finally back to The Warmer Group to line them up to have a look.
Three small holes later, they confirmed that we had no cavity wall insulation. None. A chat with a neighbour revealed that our house builders were considered a bunch of cowboys, and The Warmer Group said they had come across houses built more recently where a contractor had ‘forgotten’ to do this sort of work.
I’m not sure if I’m more annoyed about EPC inspectors that make assumptions like that (for our old house they wouldn’t do the same for our loft insulation as it wasn’t visible due to boarding), Building Control inspectors that let this get past them or the contractors who decided to save a few quid.
Still, it sounds like the work will be worth doing, if superstar Katie Wright is any kind of authority on the subject.
I also found this episode of the Fully Charged Show really interesting in terms of the starting point for any eco home: make sure it doesn’t lose any heat before starting any other measures.
As mentioned in my post about our air source heating system, we’d given the Green Homes Grant a miss as we’d heard from suppliers about problems with the scheme implementation. But for our cavity wall insulation it felt like it was worth having a go to get some help.
Well, just six months after its launch, the government scrapped its only green stimulus policy with next to no warning. We only learned about the news from The Warmer Group, who called us to say if we wanted our cavity wall insulation done under the scheme they’d need to apply on our behalf that day! Don’t you love suppliers like this?
We’ve since had our confirmation of application, meaning about 2/3rds of the cost will be picked up by the grant, which will need to be completed by the end of July.
I’m scratching my head as to why a massively popular stimulus like this — shown to be driving the take-up of energy efficiency measures and supporting the development of the green economy — would be shut down in this way. I’m unclear how the government feels it can encourage people that need financial help to improve their homes and save money. Maybe I’ll ask….
Another initiative we took recently was to get a water softener installed. Well, two, as for some unknown reason our water supply splits in two within the house!
We had looked into this before we moved, as Oxford had bad hard water, but the scale (ahem) of the problem is far greater in our new home. We’ve had to de-scale our kettle 4 times in as many months here, so were worried about the insides of our heating and water system over time.
1.6mm of scale build up within your water heating system can cause a 12% loss in heating efficiency, and given the investment we’d already made in our air source system (and a new A+ rated washer/dryer) we wanted to protect these for the future.
One of the advantages of the softeners is we can now see how much water we use on a daily basis to help us manage this too.
What it revealed is (no surprise) our bath accounts for 150 litres of this every day, way more than we expected. We can experiment with eco settings on our washing machine and dishwasher too to find other ways to reduce this.
Update: looks like we have removed 1.5kg of limescale from entering our water supply in 3 weeks. Wow
On the subject of water saving, we’re at the start of working out what to do with our garden, but it’s becoming clear that getting water to the bottom of it is going to be a problem with a 3.5m rise from the house and the nearest water butt at the bottom of that climb, with a long walk back and forth to the veg beds.
Our shed needed a fresh lick of paint (and some energy efficient lighting) so as part of that we’ve put in a guttering system to capture rainfall and store water in a more convenient location. We had to wait a maddeningly long time to get any rain to see if it worked (it didn’t; I’d installed the rain diverter the wrong way up) but now that 100 litre water butt is looking too small, so we’ll scale up immediately.
This has got us a bit excited about how much water we can capture and store in the garden. Rainwater is better for plants (and far better than purified, softened water from the house) so reusing what falls naturally just makes more sense. And as we’re on a water meter, saves money too.
Using a water catchment calculator we worked out that each side of our shed roof can capture 2,310 litres of rainwater each year. So installing guttering on the other side, and on our greenhouse, could amount to 9,240 litres of water saved just in the garden. We’ll probably add another couple water butts on the house too.
We’re planning at some point to go down the solar PV route, despite our awkward east/west roof configuration, given the success Terence Eden has had with this. But at the moment the figures aren’t working for us.
An initial estimate from a friend in the business showed that we would never actually make it pay, largely because 60% of the assumed generation would be exported to the grid.
Another reason is the terrific government idea of removing the feed-in tariff for solar generation, meaning the only income we’d get would be from our energy supplier. Their current rate is 5.5p per kWh, compared to the rate they sell electricity to me at 16.01p per kWh.
So clearly the real benefit comes in consuming as much solar energy as possible, but the problem is the times at which solar is generated compared to when energy is actually needed; at peak times. This problem is sometimes referred to as the Duck Curve.
So, storage and reuse of surplus solar looks like the way to go rather than exporting to the grid.
One way to store energy is by using solar energy to heat our hot water tank (our neighbour does this) which would use between 3 to 7 kWh a day, depending on the demand. That’s a pretty good start, but what else could we do?
The answer appears to be a home battery system. Tesla have been making waves with their Powerwall 2, but at £8,700 this would be almost as much as the solar panels themselves. And then I’d need more equipment to divert power to the immersion heater. Also, Elon Musk — what a git.
After much nerdy YouTube surfing on the subject I think I may have found what we’ll look to use, thanks to The Electric Vehicle Man, who also has an east/west roof configuration.
If you can’t spare the 15 mins to watch this, the short version is:
This last point took me down another rabbit hole of research, and there’s another video on the actual savings made using this approach. What it means is the battery isn’t just there to use up surplus solar, but to ‘buy’ energy at the lowest rates and ‘sell’ at the best rates to create the most economical way of using energy. Mind. Totally. Blown.
Re-watching that video has gotten me excited all over again about this, but I’ll need to wait for a smartmeter fitting before moving forward.