Energy Saving - Tips for Consumption

Personal finances
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We have an old oil-heated house where, during the oil era, average consumption was 2,900 liters of light fuel oil and 5,000 kWh of electricity. Nowadays, total electricity consumption is approximately 11,500–12,500 kWh with ground source heating, and the light fuel oil has been replaced by car diesel. From November to January, the total electricity consumption for the three months was 3,500 kWh.

The biggest savings in heating have been achieved by turning off the domestic hot water circulation, disabling the bathroom underfloor heating (a water radiator now provides heat), lowering the room temperature, and installing a fireplace insert in the old open fireplace.

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22

Our saving tips, which have halved our electricity consumption over the past six months:

A 30-year-old wooden detached house of 120 m2, direct electric heating, two residents, a plug-in diesel hybrid car.

Thermostats turned down by 3 degrees, the temperature of one less-inhabited room set to 15 degrees with the door closed, new windows!, an older air source heat pump given a larger role, a second, newer air source heat pump for the upstairs, sauna nights and some of the larger washes at the gym, heating the heat-retaining fireplace with the last, bottom-most, decades-old wood fibers from the woodpile, charging the car as often as conveniently possible for free, or at a price below our own combined kWh rate at public charging points within battery range.

However, the key factor in the halving of consumption is the complete disregard during the comparison period for the price and quantity of electrical energy, which was thought to be inexhaustible. I even had to tell energy salespeople that I didn’t quite remember at the moment which company’s contract was in effect.

There is also a 7.6 kWp solar power plant installed on the roof in late '22, the yield of which is still waiting for spring. Its benefit is not yet part of that halving, even though, to my surprise, it still huffs out power through fog, sleet, and the thin patches in the roof snow. Thanks to the “energy crisis” and the best NATO advocate and champion of the green transition, Putin, monitoring and awareness of electricity consumption has brought new content to the previously so dull everyday life of a consumer.

A drop of a couple of degrees in the apartment temperature isn’t felt at all. Or, well, as soft wool socks on the feet. They itch a little.

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23

I live in a 1.5-story wooden house built in the 1920s, about 70m2, which is mostly heated by a single air source heat pump (ASHP).
The shower room and toilet are heated with electric underfloor heating. Since the shower room was built upstairs 25 years ago, I keep the thermostat setting quite high just to be safe, as being too frugal could lead to major renovations.

Other heated areas include a 40m2 outbuilding which has its own ASHP with a low 8-degree maintenance heat setting.

Total electricity consumption (looking back 12 months on the energy company’s site) is about 9800 kWh per year, which I consider reasonable, but I still intend to lower it with small “Gyro Gearloose” DIY methods.

The house’s ASHP is located near the open staircase leading to the upper floor. To move the heat, I’ve built a couple of cheap copies of the €300 fans available in hardware stores. Costs: 6 PC case fans €38 and 2 adjustable DC power supplies €16. Housing made from an old birch plywood bed base found in storage €0, and other small accessories estimated at €1. Thanks to these fans, the direct electric heaters practically never turn on.

The next improvement targets are installing a shower cubicle (allowing the underfloor heating to be turned down) and building an extra ventilation duct from the upper floor to the lower floor to move rising heat back downstairs.
An easier, though perhaps less elegant, way would be to build a small false ceiling in the open entryway for the winter to reduce the area for rising air to escape.

The hot water tank is also unnecessarily large (300L), but its time will come when the domestic water pipes are eventually replaced.

There is also a large heat-storing fireplace (which the ASHP blows toward), but with current firewood prices, it is rarely used. Current consumption has been about 1.5 m3 of birch logs.

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24

Why are you keeping the outbuilding at maintenance heating? I assume there are drainage and water points there?

If not, off the top of my head I’d say the biggest savings would come from leaving it cold for the winter, unless it’s some newer non-breathable “plastic bag”?

25

I have an outbuilding that serves as a storage and hobby space. It has a thick concrete floor and some insulation in both the ceiling and walls (as well as a plastic vapor barrier), but the insulation is probably nowhere near today’s standards.

Actually, the whole space is my man cave where I can lift weights, tinker with mopeds, listen to/play music, set up watch parties, etc., in peace. So, for comfort reasons alone, I maintain a baseline temperature there. If needed, I just increase the setpoint on the air-to-air heat pump (ILP), and the space warms up very quickly.

When choosing it, efficiency was an important criterion alongside price. The heat pump in question is a GREE model; the indoor unit makes quite a whoosh during the defrost cycle and is generally more rugged in its design, while being powerful at the same time. I believe the outdoor unit weighed over 40 kg with its triple-row coils.

If the tin roof needs replacing, I’ll add more insulation to the attic floor.

For energy-saving and comfort reasons, I bought and hung thicker curtains for the house windows—designed in Finland, made in Turkey.

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Blowing more insulation into the attic is quite easy. Rent a machine from Cramo, buy the insulation, and a case of beer for the helper. It’s not much of an investment and it’s easy to do.

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27

We have a 2018-built 100-square-meter single-story detached house connected to district heating. The outdoor storage is about 10m2 and is heated by an electric radiator that keeps the temperature at 6 degrees. I’m a bit puzzled by our electricity consumption, which is around 900 kWh/month during the heating season. In the summer, practically no electricity is used.

I can’t think of any other reason for the consumption besides that electric radiator. In the HRV (LTO), the pre-heater is on practically all the time if it’s cold outside, and that’s another suspect. I can’t think of any other culprits for this consumption. It feels absurd that heating an outdoor storage unit costs €150/month at these prices. What could be the issue here?

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What are the power ratings of the battery and the series resistor? From that, it’s easy to calculate what they might cost.

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The HRV heating coil is an energy hog. The ductwork is insulated, of course, but it runs through the attic regardless, and energy losses are inevitable. It’s mostly just comfort heating anyway.

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Well, because of that concrete structure and the plastics, you should definitely keep the heating on and also ensure that the ventilation is adequate. It’s not sensible to save money on that. You might even want to raise the temperature; temperatures below 10 degrees can start exposing the building to moisture damage, as humidity won’t be able to dry out from the structures.

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31

That sounds pretty wild, that would be normal if the house was also heated with electricity.

If you can get a consumption meter for that heater, definitely get one.

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If, and probably since, the radiator is on almost all the time, it’s enough if you could just check the Watts.
If the house is heated by electricity, those consumption figures are only enough for heating a small shack, at least if you have a normal temperature in the house.
I lived in an electrically heated house for 30 years back in the day, so I have some idea of the matter.

I believe and fear that many, through misguided penny-pinching and lowering the heat, will pay for it with interest in other costs in the future.
I don’t mean those who are absolutely forced to save for financial reasons, but the cheapskates :sweat_smile:.
This latter part was not a comment on that outdoor storage case.

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33

The heating requirement for a normally insulated space is typically 70-75 W/m2. So, in a 10 m2 space, that’s 512 kWh/month. In your case, there are many variables: outdoor temperature, insulation, and indoor temperature. In a poorly insulated storage unit during extreme cold, that 500 kWh is easily reached. A meter will tell you for sure.

34

My own 80m2 house only hits that 900 during the coldest months, with a perfectly normal indoor temperature. The average for the winter months is significantly lower. Of course, houses vary; yours is unlikely to be comparable to a house built in 2018 if you’ve been living in it/them for 30 years.

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35

Yeah, the size and age of the house (2009) and I also had a garage and storage unit (63 square meters), where electric underfloor heating probably makes it roughly comparable.
Consumption was on average about 2100 kWh/month.
Fortunately, I haven’t lived there for 3 years now :sweat_smile:

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36

At least to me, this has been marketed as energy-efficient. Is it not, then? I’d gladly turn off that pre-heater, but according to the manual, only an installer/technician is allowed to do that. I also don’t know if this could cause the equipment to freeze or cause other issues.

Radiator 750W and I think the pre-heater was 500W. You can certainly get some high consumption from those when both are running.

I’ve had a bit of a feeling that these figures are similar to an electrically heated house. I’m not really sure what to do with the outdoor storage, either. It needs background heat because of a few things, but those could be brought inside for the winter. Regarding the structures, I don’t know if it can be left unheated or not.

If anyone has tips on what to start looking into here, I’d gladly take any ideas.

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That radiator alone consumes 6,570 kWh per year if it runs at full power constantly; it’s likely not on all the time depending on the room’s volume and insulation, but it gives a good estimate of consumption—quite a lot in any case.

Usually, that pre-heating resistor is on all the time in cold weather; at the very least, it’s worth turning its temperature/thermostat down a bit. I don’t believe the equipment will freeze even if you turn it off, though the heat recovery unit (LTO) will then blow colder air inside, which will also need to be heated.

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Set the supply air temperature as low as you can stand—I have mine at +14—and HRU (Heat Recovery Unit) defrosting via bypass is my own solution. I don’t have enough expertise for more detailed comments, so I don’t know if this applies to your situation. Given how much electricity you’re using, though, I would have a professional visit the site if you plan on living in the house for a longer period.

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39

Vallox’s website has information about that core heating. They don’t recommend it as a primary heating method, but purely as comfort heating, which should be kept as low as possible.

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40

Best energy-saving investment: €15 electricity meter.

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