See 4:40 in the video 
It’s more to it though. Lots of heat pumps aren’t really heat pumps, not by design. They are air conditioners that also work to some degree as heat pumps. However, nowhere near as a purposely designed heat pump for cold weather. In principle they are the same thing. “Air conditioners” will work down to 0 degree perhaps, while real heat pumps works down to (and sometimes well below) -20 deg. Another thing to remember is not to put the heat pump in “auto”. In the winter, always put it on “heater”, or it will start to cycle between heating and cooling. Just the sun through the windows could be enough.
I got a Mitsubishi. Mitsubishi, Panasonic and Samsung seems to be what works around here.
Right; that’s what I thought. Key detail left out.
The heat pump I have here is “rated” down to -15C. Yet, as I said, it is “useless” below about +5C. I mean, it “generates heat”, no doubt down to -15C, but with a COP < 1. Of course, nobody will realise it, because, hey, it “produces heat” and they will think “gosh look how wonderfully green we are”. 99% of people have absolutely no means of discovering that the COP is < 1 and this the capital cost is just a slowly (sometimes not so slowly) corroding dead weight.
In your super efficient house one can make it work, but only because you can heat those with a few kW, even with a delta T of 30K. The average “5-bedroom” detached brick house will need something like 20kW. My heating system is sized for a 25K delta (very unusual in the UK; traditionally they design for a lot less) and the oil burning boiler is IIRC about 25kW.
We had a large extension done in 2004 and that has 20cm of celotex in the roof.
Peter wrote:
The heat pump I have here is “rated” down to -15C. Yet, as I said, it is “useless” below about +5C. I mean, it “generates heat”, no doubt down to -15C, but with a COP < 1
That doesn’t sound like a heat pump for cold climate. COP at -20 should be around 2 (or more). SCOP should be around 4-5. The best ones have more than 5.
Peter wrote:
In your super efficient house one can make it work, but only because you can heat those with a few kW
My house isn’t super efficient, far from it. Brand new so called zero houses are super efficient. My house is several classes below that. During the winter, the heat pump is not enough to heat up the house, too much leakage and too much temperature difference (it could easily be 40 degrees or more). The way we set up things:
In the house we have a couple of electric “panel heaters”. They are set to 10-15 degrees. We don’t need them, but in case the heat pump explodes or something, the house will not become -20 all of a sudden. Then we have floor heating in the basement and bath rooms. Bath rooms are always on, but the basement are on only during the winter. The heat pump is the main heating. We also have two fireplaces, which really heats a lot when it’s cold. It’s also comfy and cozy
In the cottage we only have one single panel heater set to 10 degrees. The rest of the heating is wood. When we come, the first thing we do is to fire up the fireplace The bathroom has heated floor though.
It really is all wrong in the video. Yes, there are super efficient houses (zero houses), but they are 1 in a thousand perhaps, and hardly need a heat pump at all. The normal way is something similar to what we have. A few electric heaters just in case, heated floor in the winter, heat pump for the baseline all year round, then fireplaces to burn wood when it’s cold.
Peter wrote:
super efficient house
I would think what is considered “super efficient” in England is quite different from what we would mean by the term in Scandinavia. We simply have different climates.
40+ years ago, a new school was built at Linnacleit on North Uist. It was heated by heat pump, built using marine standard materials due to expected salt exposure. A few years later it was replaced with an oil fired system, due to corrosion problems .
I grew up with a coal-fired Aga. One hot room, two warm rooms, and the rest of the house unheated. It was from the 1950s, so newer ones might be more efficient, but the underlying design probably hasn’t changed much; nowadays it’s a status symbol. We had a coal Parkeray at the other end of the house which ran a few radiators, but we only lit it in very cold winters. Happy childhood memories, but I’m now soft and take for granted the thermostat and lack of heavy lifting.
Two neighbours in France have heat pumps. It keeps the house at a stable 15C and you light the woodburner in the morning and when you get home from work to bring the temperature up. The two work well together if you have your own wood (or a cheap source) and government grants for the equipment and installation.
We have solar panels on the roof at home, installed by the previous owners. Feeding into the grid it’s a nice little income stream. Friends had their 1960s Economy7 storage heaters wired to their new solar panels, which they say is efficient.
Insulation is probably the most cost-effective. Unfortunately UK planning laws prevent e.g. double glazing on older houses, which would benefit the most.
Airborne_Again wrote:
I would think what is considered “super efficient” in England is quite different from what we would mean by the term in Scandinavia. We simply have different climates.
It’s not the climate, it is about what people spend their money on. This summer I visited England and Wales (the last time was more than 25 years ago) and got quite a culture shock. I think, I now understand what people mean when they say that Germans do over engineer everything. I think that they are mostly right though I believe that it’s more of a central European thing and not limited to Germany alone. But when it comes to keeping the warmth inside the house I have the impression Britain is around half a century behind the continent. Everywhere between Norway and Greece poeple who can afford it buy decent doors and windows but the second largest economy in Europe still has leaking sliding windows and 2 pane windows is something one upgrades to. On the other hand my 10 year old car almost looked like a classic between all new cars there. Sorry, if this reads like a rant, it is just what I observed.
With this differences in building and insulation standards in mind it is no surprise that the solutions for reduction of energy consumption need to be different between countries.
Capitaine wrote:
Insulation is probably the most cost-effective. Unfortunately UK planning laws prevent e.g. double glazing on older houses, which would benefit the most.
The glass itself is usually not the problem, it’s usually the wider frame on plastic windows which makes modernized windows on older houses look meh. It’s only a matter of how much money one wants to throw at the problem..
You went to some funny (or poor) part of the UK
A time warp from the 1960s. Anybody with money and a brain will have had double glazing 30-40 years ago. Not the triple glazing though, which is used in some countries. 30k kitchens or bathrooms are quite common – mostly equipped with German products
But yes people here do blow money on cars, inexplicably.
You can usually do double glazing on listed buildings. It must not be visible externally. In extreme cases, it can be done as a separate sheet, further inside. But for sure I would never buy a listed building.
My recipe for avoiding a lot of problems:
Move where you turn on the house heating and the air conditioning for perhaps 10 days or nights a year each. As a result I don’t care very much how efficient those systems are, only that they are cheap to buy and replace.
Fly where it is inexpensive and hassle free, where most days are VFR, and where owning an aircraft is relatively straightforward.
Spend the money saved to vacation elsewhere in May/June and early September and when there ride a motorcycle to avoid hassles with traffic. Get out of there before the weather turns for the worst.
Buy Japanese and not German, at least for anything (e.g. cars) made in the last 30 years. Spend the money saved to buy something of value that doesn’t depreciate.
Greetings from Lago di Como
I’m fully electric now. All Tesla.
The only thing that I would now recommend for others following the same path would be to only buy a single Powerwall and then buy a used Tesla car battery and integrate it into the Tesla Gateway instead of buying multiple Powerwalls.
The cost of a salvaged (but still perfectly usable) Tesla car battery is usually around $20k-$25k but the total useful capacity is often around 75-80kWh and thus the installed price per kWh is 1/4 of that of the Powerwalls.
LED lights are an instant must.
Hot water is also a surprising drain on energy (you see it one you monitor total current/consumption from your system). Having on-demand hot water heaters isn’t really compatible with solar because they often draw in excess of 20kW, which is more than most solar+battery installations can provide at night.
This is a big factor when considering off-grid solar: the batteries often can’t output more than 3-8kW each.
My system provides ~15kW continuous, which is enough to run multiple appliances, but can’t support cooking, running the hot water heater and houshold activities at the same time if I use an instant hot water heater.
If I would have installed a Tesla car battery instead, I would have no problem if I went with the Tesla Model S battery (here is an older example, it has been done for a while:
)
So, having a heat pump hot water heater, on-demand hot water heater, or super-insulated hot water heater is really important in colder climates.
Aside from that and general household heating (which has already been covered at length here, so I won’t mention it), having an efficient stovetop is helpful (induction) and really working on insulation is a massive point. I can’t overstate this one, even though it is obvious.
Spending a few thousand on home insulation is worth more than almost all other efforts in my experience.
If I had to rank what has helped my home the most, I would say:
1. Having a system to monitor power consumption over time (Tesla app in my case) so I can test what is consuming energy, and how much, when.
2. LED lighting
3. Hot water heater (efficient type or better insulation)
4. Insulation/airflow
5. Per room heating controls
