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I have a 1974 24 x 40 pre-fab home which is mostly put together like a mobile home but has 2x4 exterior walls and I was thinking of changing out the oil fired system to put in a heat pump. Any thought on would it maybe save me a few dollars in the long run. It is our summer place but here in Delaware we get very cold temps in the winter and I need some heat to keep the pipes from freezing. I also don't have an AC unit hooked up and I also thought that a heat pump would be easier to install in my place. It sits on a block foundation and that is why I did not hook the old separate AC back up that came from my old single wide mobile. I don't really want to punch a big hole in the foundation to run the air ducts from the separate AC unit. Any input would be greatly appreciated. Also what size (tonnage) do you think I would need for a 24 x 40 place?

Thanks,
Ron

Hi Ron,

A heat pump would not be advisable in the cold temp area in which you live. Most are only good down to around 35 degrees and the very best ones only give some heat down to the twenties.


Even then, they need back up auxiliary heat to produce temps desired in the home.


They also reverse operation for heat mode placing the cold evaporator coil outside. It would need steady defrost in those temps and defrost sensors and boards fail often.

When they do, you have no heat and not being there would not be good.


IF it is not used in winter, I would winterize the home and then not have to have heat for the pipes.

Or, insulate foundation walls, seal and insulate belly good, run pex water pipes and insulate those well.


That would greatly reduce amount of heat needed to protect the pipes.

As for as size needed for any unit, go to www.hvac-talk.com and look in top toolbar for HVAC Calc and click on it.


That is a homeowner version of the Manual J Load Calculation needed for proper sizing of any and all hvac systems.


Thanks,
Robert

Thanks Robert, I was not sure. Around where my place is a lot of the newer homes are being built with heat pumps and I was thinking that they just might not cut it in the coldest of times. I guess they must have some kind of backups also.

Thanks again,
Ron

Hi Ron,

You're very welcome, happy to help. They definitely must have back up heat starting at about 35* and down.


Thanks,
Robert