HRV

This controller is what I see normally. One day the idiot light was blinking and it says [replace filter]. I went up inside the roof cavity above the ceiling, to check the filters. On top of the pink batts insulations are numerous large conduits from the HRV units.

The air hoses originate from this box containing an electric fan and a filter. There are two of these fans installed inside the roof cavity, hanging from a beam just under the roof tiles.

The other end of the air hoses lead to 6 large holes cut in the ceiling. Some times I can hear the rush of air coming into the rooms. The fans are pushing hot air down into the rooms and colder air out, under the doors to the garage and bathrooms. NZ houses are air-tight especially in winter when windows are fully closed.

While waiting for the replacement filters , I shut down the HRV for 4 days. My windows start tearing in the morning. The HRV has been keeping the humidity down, just as claimed in the brochure. Now it became more obvious. I plugged in the dehumidifier for a few days, removing about half a litre of water. After putting back the new filters I restarted the HRV and disconneted the dehumidifier.

dehumidifier

It seems that my new heat pumps with the HRV working together, are keeping the air inside the house quite dry.

I was using oil storage heaters for my winter heating for 16 years until recently. Three oil heaters came with the house; but a dehumidifier was required to run full time to stop the windows tearing up in winter. Those oil heaters are good but low tech and did not allow instant heat control because I was using off-peak current which was controlled by a time clock. The power supply is turned on automatically at midnight for 4 hours heating the oil inside the heaters. During the rest of the day heat is radiated slowly to keep the house warm.

I installed heat pumps this year. These Fujitsu's are high tech and very efficient, similar to air-cond split units in Malaysia; but working in reverse: hot air IN and cold air OUT. If required, in summer, I can throw a switch at the outside unit and use it as a normal air-cond: cool air IN.

second heat pump

Having no experience with heat pumps, I did not realize that the cold air OUT was extremely cold. That first heat pump killed my treasured money plant. This time I place the second heat pump away from all my plants outside the house.

My money plant was healthy and strong. It was a terrible experience for me watching it keel over slowly and die last winter; frozen to death!

frozen

keeled over

trunk removed

gone!