Testing heat pump in cottage + Bitcoin mining on mobile Internet failure

Let's do some recap about testing photovoltaic installation in our cottage in Beskidy mountains, Poland.

I need to stress out that the house was built in mid '90s following then contemporary technical terms. It was insulated few years ago and heating source (from coal) was replaced with heat pump last year.

It's a regular brick house (all-year-round), but nobody lives there on permanent basis. Before the change of heating source, we needed to go there from time to time to light up the furnace in order to keep the temperature above 0 C. Lest it falls below 5 C you might have a whole new renovation to do due to the frosting water in pipes and appliances might damage them.
So, in order to calculate the former heating costs, you need to take into account travel cost (80km one way), time consumed etc. Go figure, when it was below 0 C outside, there was a need to visit the house once a week or so. If you wanted to go there on winter you would have to go there two days prior and load up the furnace or get someone do it. We have a neighbour that would help, but since he refused to get paid we didn't want to impose ourselves and keep that option for situations when up against the wall.

Consumption details

Please look at the following charts. The first one with only two colours shows how much energy was bought from the grid and how much energy was generated. As you probably have noticed already, we remotely turned on the heating on 12th Feb with the indoor temperature being 9.8-12.5C (Day-Night). I don't want to make things even more complicated, so I excluded energy stored in batteries. On the first day, it got around 30 KWh from the grid. For the next 2 days the system downloaded over 70 KWh per day with one day at 80 KWh. The consumption remained somewhat stable from 13th up to 18th with consumption over 60 KWh per day. We left on 19th and turned off the heat pump using about 40 KWh. The consumption includes regular use of electricity (lights, charging devices etc.).

So generally speaking our 5-day stay resulted in less than 400 KWh bill (heating before arrival included, strictly during days of stay, we bought ~280 KWh). It's about 80 PLN/$20 per day of pure energy cost (in Poland the KWh is slightly cheaper, but for this post sake let's keep it even)

ChatGPT told me that, the average annual electricity consumption for a family of four in Poland depends on the type of heating and household appliances usage. Single-family house without electric heating – around 3,500–5,000 kWh per year which is 9-13 KWh per day.

Let's compare these figures with how much it would have costed if it hadn't been for heat pump. As far as I remember, the stove we had used to have a 200 kg hopper, which would last for 3-4 days max in this weather conditions (-10C at night). Let's also assume someone would come and start the furnace on 12th Feb and it would operate until 19th - it's safe to assume it would use up 1.5 hopperfull of coal. The average price of coal in LeroyMarlin supermarket is 1.65 PLN/kg, which gives us the total cost of 495 PLN.

5-day stay would cost us 70 PLN/day. Without electricity cost.

Of course, in both cases the costs would decrease because the house would accumulate more energy/heat and simple multiplying both figures by number of days in month would give us false and exaggerated results.

Back to the project

Look at the beauty below. We are trying to get things done the way that would impact our neighbours the least. We have installed this generator in a garage which required us to drill two wholes in its walls for air intake and fumes exhaustion. I guess this attitude isn't something common. Today we've been on our land only to notice other neighbours have been using their generators placed freely outdoors creating sound way above acceptable limits. So I guess the other neighbours won't object to our generator running.

The 24 hours test have proven that I can't mine Bitcoin while on mobile Internet. I got one piece of advice to try using different 3g router and I will follow that route. The miner logs suggest that the Internet connection isn't stable.