House 001 report
Performance, lessons learnt, conclusions and plans for Stage 2
Autonomy
The goal was full autonomy by energy and water year round. Reality for now: with current 6 KW of solar panels and 45 KWh of batteries we have autonomy from mid February till mid November. During sunny time the energy utilisation is great, as all excess energy is used to charge 2 EVs. Peak daily sun energy collection was 17-18 KWh. In order to reach full energy autonomy, in Stage 2 we plan to install 4 KW wind turbine and 4-5 KW more of panels.Water. Around 500 liters was used monthly while the shower was not yet launched. All this amount could have been replenished from rain (except some winter months) if the water quality was good enough. Too much iron and manganese was tested in rain water most likely because of leakage from roof material. Decided to use rain water only for plants watering. If industrial iron removal system is installed, we could say we were autonomous by water. But with shower we’ll need more water catchment areas and more water storage. Will be done in Stage 2.
Energy Efficiency Metrics
Electrical Energy Used for heating season EUI = 42.77 kWh/m2Heating Demand = Electricity Used X COP.
Effective COP of our heating system is hard to estimate. Let’s assume it’s 3.
Heating Demand = 42.77*3=128,31 kWh/m2
This is how far we are now from Passive House standard of 15 kWh/m2. And from Nearly Zero Energy Building standard of 20-50 kWh/m2. Well-insulated modern home allowance is 50-100 kWh/m2.
Well, this is the reality. We are accepting it and planning what to improve in Stage 2.
P.S. High Energy Efficiency was not our main goal, while full autonomy was and is. Passive House level is great, but only if a house remains affordable. Anyway, we will focus more on Energy Efficiency in the next projects.
Embodied Carbon Savings
Based on the metrics provided by the Climate Solutions Metrics Garden we have the next calculations:- As of February of 2025 our solar system has generated around 5 MWh, which is enough to displace 2 tons of GHG emissions;
- House 001 does not use gas/oil/coal powered furnaces or wood burning stoves, which gives 1 ton of GHG savings;
- Total Embodied Carbon during lifecycle of a traditional single-family home of 30 sq. m. would be 15 tons. Our low carbon home of 30 sq. m. is 6 tons, which gives 11 tons of GHG savings;
- 92 sq.m. of ivy planted gives 0.1 ton of CO2 absorption.
Of course we also save daily by using EV and charging it from our solar system, but decided to not count this here as it was outside of our initial goal.
Insulation and Circular Economy
Sawdust, that we used for insulation is the cheapest possible material. It is fully natural material, fully recyclable, widely available locally. That’s why we’ve chosen it.However, it settles significantly, especially in walls. Also it is highly flammable, if not mixing with lime, but since lime manufacturing emits a lot of CO2, we decided to not do it.
For now we are very interested to start using blown-in cellulose. We plan to replace walls insulation of House 001 with it and use it for all future projects. Not only this material solves the issues with sawdust I mentioned, there is more - it creates fully circular economy, as it allows to transform unneeded cellulose materials, like paper and cardboard, to a high performance insulation. That’s why it has the lowest embodied energy out of all insulation materials.
Construction
House 001 uses light metal frame, OSB and wooden laths. This construction appeared to be not strong enough, also it has relatively high CO2 footprint and complexity because of using metal.For future projects we are going to use panels based on wooden I-beams that we manufacture in-house. They can be insulated and have interior and facade materials installed, but this makes them too heavy to work without mechanisation. Instead we will prepare them for blown-in cellulose insulation once a house is assembled. Sauna of House 001 will be built using this technology.
Foundation
We were installing geo screws ourselves and it was fun! But as House 001’s weight was increasing, we started to notice uneven sag. As of the end of 2024 this was fixed but it required a lot of work that should have been done together with foundation - ground compacting before installing screws and also connecting screws together using metal beams that are dug and therefore hidden. Great lesson learnt! Would same tons of effort in future projects.Heating
The idea was to use warm floor and walls for heating. This should have been working great is installed properly. We did not investigate enough and installed too little of water pipe, and also plywood that we used as part of floor - is more of a thermal insulator than a conductor. If using low temperature heating, it’s better to hire professionals or to perform a deep research on how to do it properly, as you can’t fix this afterwards.Composting toilet
Is great thing overall, odorless, allows to save water and not build a septic system or connect to a sewage. But it requires maintenance from time to time. Also composting toilet sucks air all the time out of the house, which is not good for energy efficiency in winter. In order to overcome all this we plan to build a system that would work similarly to incinerating toilet, but be way cheaper. Technical space
Any house should have a space for equipment needed for its life support, and especially this applies to an autonomous house.Water boilers, batteries, inverters, water storage tanks, air recuperators, pumps, you name it.
House 001 lacks this room and this is what definitely needs to be addressed in future projects.