4 ms·

The issue I’ve seen is need for heat goes up a LOT in older houses when it gets that cold, and the heat pump without resistive heat performs a lot worse (like 2

The issue I’ve seen is need for heat goes up a LOT in older houses when it gets that cold, and the heat pump without resistive heat performs a lot worse (like 2x+ worse). So it’s a noticeable combination

KptMarchewa 4y ago
Why would you install heat pump without properly insulating home first?
- sokoloff 4y ago
  Because the labor to properly insulate a home can be quite extensive, while the labor to install a heating unit is typically less than half a day. Take a structural brick house built with no cavity insulation, plaster walls, and a finished interior and try to get any amount of additional insulation into the walls. You end up having to destroy and repair the finished plaster walls, which is obviously prohibitive from a labor cost standpoint. Those projects can be (and usually are) done when remodeling/redecorating is already planned (so you don't double-pay for finish work), but are economically unrealistic to do just to save on HVAC.
  - KptMarchewa 4y ago
    IDK about US wooden houses, but here isolation for old building is usually done on the outside on the top of previous finish with styrofoam or mineral wool: https://d-art.ppstatic.pl/kadry/k/r/1/70/9e/60644af2aec93_o_full.jpg https://d-art.ppstatic.pl/kadry/k/r/1/70/9e/60644af2aec93_o_... >economically unrealistic to do just to save on HVAC That depends on how much the HVAC costs... I saw some videos from last USA freeze where people had ice (!) inside of their homes - I doubt heating that is in any way economical.
  - theluketaylor 4y ago
    There are plenty of insulation firms that specialize in insulating old homes without ruining the finishes. Typically you cut a small plug, either from the outside or inside depending on the construction method and mechanically force (typically blow) cellulose fibres into the wall cavity. You need one plug per stud bay, but repairing those is a pretty simple job compared with tearing down all the finishes. Air sealing is tougher, but techniques like aerobarrier where an aerosolized polymer is sprayed throughout the home while it's under positive pressure has made air sealing fairly simple. Stuff like that can plug up to multiple inch gaps
    - sokoloff 4y ago
      The "cut a small plug into each stud bay" works very poorly when the wall material is 9" thick structural brick and there are not studs, but rather lath and plaster (and often wallpaper) on furring strips.
    - iso1631 4y ago
      If you seal your house you have to worry about moisture removal otherwise you're going to be getting damp issues.
- onphonenow 4y ago
  Lath and plaster can be extremely expensive to repair. Sealing old houses has problems in terms of moisture- many old houses depend on evaporation in various ways- list goes on

KptMarchewa 4y ago

Why would you install heat pump without properly insulating home first?

sokoloff 4y ago
Because the labor to properly insulate a home can be quite extensive, while the labor to install a heating unit is typically less than half a day. Take a structural brick house built with no cavity insulation, plaster walls, and a finished interior and try to get any amount of additional insulation into the walls. You end up having to destroy and repair the finished plaster walls, which is obviously prohibitive from a labor cost standpoint. Those projects can be (and usually are) done when remodeling/redecorating is already planned (so you don't double-pay for finish work), but are economically unrealistic to do just to save on HVAC.
- KptMarchewa 4y ago
  IDK about US wooden houses, but here isolation for old building is usually done on the outside on the top of previous finish with styrofoam or mineral wool: https://d-art.ppstatic.pl/kadry/k/r/1/70/9e/60644af2aec93_o_full.jpg https://d-art.ppstatic.pl/kadry/k/r/1/70/9e/60644af2aec93_o_... >economically unrealistic to do just to save on HVAC That depends on how much the HVAC costs... I saw some videos from last USA freeze where people had ice (!) inside of their homes - I doubt heating that is in any way economical.
- theluketaylor 4y ago
  There are plenty of insulation firms that specialize in insulating old homes without ruining the finishes. Typically you cut a small plug, either from the outside or inside depending on the construction method and mechanically force (typically blow) cellulose fibres into the wall cavity. You need one plug per stud bay, but repairing those is a pretty simple job compared with tearing down all the finishes. Air sealing is tougher, but techniques like aerobarrier where an aerosolized polymer is sprayed throughout the home while it's under positive pressure has made air sealing fairly simple. Stuff like that can plug up to multiple inch gaps
  - sokoloff 4y ago
    The "cut a small plug into each stud bay" works very poorly when the wall material is 9" thick structural brick and there are not studs, but rather lath and plaster (and often wallpaper) on furring strips.
  - iso1631 4y ago
    If you seal your house you have to worry about moisture removal otherwise you're going to be getting damp issues.
onphonenow 4y ago
Lath and plaster can be extremely expensive to repair. Sealing old houses has problems in terms of moisture- many old houses depend on evaporation in various ways- list goes on