Question on heating/cooling needs in relation to insulation levels and required ventilation
I have been running some numbers on potential heating and cooling equipment for a build-out, and am running into some problems getting consistent data/specs.. I wanted to pick some brains here as to whether some of my root assumptions are actually valid, or whether there are factors I have missed or glossed over.
Because there is not a lot of narrowboat-specific data for heating and cooling devices, I am trying to roughly equate the heating and cooling needs of a narrowboat with the equivalent heating and cooling needs of an average-quality trailer(caravan) or RV of similar size, taking into account a few significant differences:
- a narrowboat sits with half of its structure in a fairly effective heatsink medium (canal water) and so would be more resistant to rapid changes in temperature over a reasonably large portion of its structure.
- On a narrowboat, most oxygen-using appliances (diesel/propane heaters, cooking appliances. solid and liquid fueled heating stoves, etc are housed 'inside' the living area and thus per ISO and BSS requirements the boat must have adequate permanent passive ventilation to supply combustion air to these devices as well as let combustion fumes exit the living area safely (aka easy pathways for outside air to get inside), while with the average caravan/RV many of those appliances are 'outside' the living area and thus require less permanent passive ventilation into the living spaces and therefore less hot/cold air exchange.
- Construction materials: Caravans are usually made of a sandwich of thin aluminum skin, some sheet foam, sprayed foam, or fiberglass insulation,, and an interior structural panel, usually some kind of laminated wood or chipboard, while narrowboats are usually constructed of much more substantial solid steel sheets, sometimes with interior foam panels of spray foam applied as insulation. I would consider the average caravan to be 'leakier' than a narrowboat shell as far as outside air infiltration. Both vehicles likely use single pane glass or acrylic windows in metal frames.
What I hope to eventually quantify is what improvements could be expected by:
- eliminating all combusting appliances inside the shell and therefore significantly reducing the amount of required permanent passive ventilation,
- using an outside air heat recovery unit instead of just open passive ventilation (I understand that this is not something BSS would currently accept as a passive ventilation replacement)
- using a thicker insulation layer inside the shell and double-pane insulated windows.
Are there any other significant differences between the two vehicle types that would relate to HVAC needs? I will be happy to publish my results here if I actually manage to find some useful and consistent connections and/or data between the two that may help future builders/planners.