3 ms·

I haven't done any savings calculation/break-even forecast. The electricity prices are very volatile.

• jaclaz 4y ago
  I just wanted to point out that you were in a particular situation (obsolete existing plant probably needing replacement anyway at a possibly not too different cost) + state incentives (even if only 30% of the man hours) and you had the money to invest. Usually the break even point should be in the 5 or more years range (unless there are more substantial state incentives) for a "plain" replacement (i.e. with a working furnace + conditioner replaced by a heat pump). Anecdotally, a couple of years ago (in a shop, not a house, but the reasoning should be the same) I replaced a gas furnace (that was to be replaced anyway) and an air conditioner (that also was likely to fail being old enough) with a new heat pump. Both had a heat exchanger and heated/refreshed water that circulated in a few fan-coils, so there was in practice no need of masonry or hydraulic work besides replacing the (external) units. Replacing them with a new gas furnace + new conditioning unit was quoted around 4,000 Euro, whilst the new heat pump was quoted around 10,500 Euro, at the time it was possible to have 65% state incentive (directly credited by the supplier), so I paid only around 3,700 Euro, i.e. roughly the same as replacing the old units with the same ones instead of using the new technology. Without this (very substantial) incentive I calculated that it would have taken a little less than 6 years to get even at a projected saving of around 1,100 Euro/year.