Self build house - is MVHR worth cost?

[SteamyTea]

2 minutes ago, Iceverge said:

The house i grew up in winter had 2 modes.

Did it have lots of 'thermal mass'?

[joth]

2 hours ago, SteamyTea said:

Compared to what though.

 

May sound an odd response  but you would save the running costs by switching your MVHR off and the building airtightness would remain unchanged (may get a bit smelly indoors).

Doing that is not the same as comparing a house with an ACH figure below 1 with MVHR and a non MVHR house with an ACH figure of 7.

Volume of the house makes a difference as well.

Compared to running the fans but without any heat exchanger. What else could it be?

This is obviously not a comparison of a leaky house vs airtight with mvhr, but as an mvhr designer it's the only sane number to provide, given the instrumentation available to the device. 

 

[SteamyTea]

1 hour ago, joth said:

What else could it be

The options I showed.

 

This is often the problem with energy comparisons.

I wonder if anyone has correlated the efficiency of MVHR against HDDs.

[Temp]

We installed a system even though our house probably isn't very air tight.

 

Would do so again. Not for energy saving reasons but simply for the air quality improvement it gave us. First few nights it felt like waking up in a tent.

[joth]

2 hours ago, SteamyTea said:

The options I showed.

 

This is often the problem with energy comparisons.

I wonder if anyone has correlated the efficiency of MVHR against HDDs.

But an mvhr unit has no way of measuring how much energy the building would be using on heating if it was to be used under some other hypothetical conditions, such as if it were turned off.

It has measurements for air flow rate and incoming/outgoing air temperature so the only thing it can realistically tell you is how much energy it has recovered from the outbound air in the operating conditions it is actually working under. 

Edited 16 hours ago by joth