Wooden house built in 1930 with 2 floors, with neglected maintenance. The tiles are missing on large parts of the roof, replaced with tarpaulins. The attic's wooden construction is in poor condition.
I will now install a wood stove with a rectangular accumulator tank of 7m3 and have decided to have an open expansion vessel at a height of about 8m in the attic. This will cause the cold water to absorb a lot of oxygen, so I plan to have a stainless expansion vessel manufactured of about 400l and allow hot water from the accumulator tank to circulate through the expansion vessel to prevent oxygen absorption and have an efficient deaerator connected to the lower part of the accumulator tank. I have installed modern larger radiators on the lower floor with a hole in the wall and filters for a low-temperature system 20-40C with heated cold supply air for a future exhaust air heat pump. Previously it was a 60C system 14kW with thermostats on each radiator. Now all the thermostats have been removed due to noise, and the indoor temperature is controlled manually with a simple new electric boiler 5kW for the time being. The energy consumption decreased from about 300 to 175kWh/m2/year. The intermittent exhaust ventilation consists of a humidity-controlled bathroom fan and kitchen fan. If the expansion vessel is uninsulated, the air temperature in the outdoor-ventilated attic will increase. Will this cause the wooden construction in the attic to dry out? I am also considering installing some of the old radiators in the outdoor-ventilated crawl space. What could be the consequences of this?
I have my own firewood!
I look forward to your comments.
Kind regards
Alma40
I will now install a wood stove with a rectangular accumulator tank of 7m3 and have decided to have an open expansion vessel at a height of about 8m in the attic. This will cause the cold water to absorb a lot of oxygen, so I plan to have a stainless expansion vessel manufactured of about 400l and allow hot water from the accumulator tank to circulate through the expansion vessel to prevent oxygen absorption and have an efficient deaerator connected to the lower part of the accumulator tank. I have installed modern larger radiators on the lower floor with a hole in the wall and filters for a low-temperature system 20-40C with heated cold supply air for a future exhaust air heat pump. Previously it was a 60C system 14kW with thermostats on each radiator. Now all the thermostats have been removed due to noise, and the indoor temperature is controlled manually with a simple new electric boiler 5kW for the time being. The energy consumption decreased from about 300 to 175kWh/m2/year. The intermittent exhaust ventilation consists of a humidity-controlled bathroom fan and kitchen fan. If the expansion vessel is uninsulated, the air temperature in the outdoor-ventilated attic will increase. Will this cause the wooden construction in the attic to dry out? I am also considering installing some of the old radiators in the outdoor-ventilated crawl space. What could be the consequences of this?
I have my own firewood!
I look forward to your comments.
Kind regards
Alma40
Hello and welcome to the Byggahus forum!
Theoretically, it must work. Whether it does in practice depends on the volumes in question. The reason why moisture problems were rarely an issue in crawl spaces or cold attics in the past was due to extensive heat leakage upward and downward. There is no doubt that wooden houses function better with a lower level of energy efficiency. As for the wood in the attic, it depends on how damaged it is and by what. Moist wood can always dry out. Any rot damage does not always need to be removed. I am not the right person to assess the HVAC aspects, but it doesn't sound unreasonable to me.
Theoretically, it must work. Whether it does in practice depends on the volumes in question. The reason why moisture problems were rarely an issue in crawl spaces or cold attics in the past was due to extensive heat leakage upward and downward. There is no doubt that wooden houses function better with a lower level of energy efficiency. As for the wood in the attic, it depends on how damaged it is and by what. Moist wood can always dry out. Any rot damage does not always need to be removed. I am not the right person to assess the HVAC aspects, but it doesn't sound unreasonable to me.