So much depends on the type of building and its condition. If it needs new windows and cladding, then consider adding some insulation - certainly air tighten the walls with a membrane. If it needs a new roof, upgrade the thermal performance at that time.
I've done analyses for century-old masonry bearing wall municipal buildings and concluded that insulating the walls doesn't make economic sense. I have a rough guideline for my area (New England, USA - hoping to become the next Canadian province) that I like to see the design load of a building get down to 20 BTU/hour/sf (63 W/m2) before converting to heat pumps.
In my online classes about decarbonization (Heatspring and Fine Homebuilding), I stress that when making these enclosure decisions it's important to identify all of the existing deficiencies that go beyond energy use. Is there mold? Water in the foundation? Pests? Recurring frozen pipes and ice dams? The value of thermal enclosure upgrades may be far more significant in rectifying these than in the energy saved.
Once the decision to convert to HPs is made, it's important to understand the real design load of the building. Fossil fuel systems are almost always oversized. We datalogged some of the aforementioned masonry municipal buildings during a very cold spell. They had existing NG heating systems sized at 50 BTU/hr/sf, our calcs showed 30, and actual peak was under 20. That saves a lot on heat pump costs, and also makes it easier to fit the new systems in the building.
I think focusing on insulation as the most important component of "fabric first" is a mistake. Airsealing is cheap and essential.
Some blower door operators give the usual report about airtightness in air changes per hour at 50 Pascal (---ach50) but also put airtightness in the form of how big a hole in the building envelope a given level is equivalent to. So "your house leaks like there's a 10cm x10cm hole in the outside wall" is a lot better than "your house leaks like there's a 50cm x 50cm hole in the wall."
"...Meeting this peak with renewables would require a 28× increase in January wind generation or a 303× increase in January solar, with excess generation in other months. Highly efficient building electrification can shrink this winter peak—requiring 4.5× more generation from wind and 36× more from solar."
No matter which increase is used, 28X/303X or the 4.5X/36X, that's a massive amount of land that will be required. And a HUGE CapEx in order to deploy. AND, to bring it home, the massively long timeframes to do all of the required studies to satisfy all of the policy statements/standards that (irony alert) have been put into force in govt by....environmentalists.
So, once again (heh - THE "evergreen" phrase for me over the years), WHO is going to pay the cost of either of the X increase sets, and WHO is going to have the money and time to go up against the entrenched NIMBY and BANANA eco-environmentalists that took the high ground years before in order to keep any of the needed building for those REs from happening.
And as to the cost, let's be blunt - you'll have to rely on eco-VCs to fork over the investment as this administration, and rightfully so (govt has almost ALWAYS proven to be a horrible VC due to political connections making the deals and not realistic ROIs). And those VCs are rather loathe to open up their piggybanks. Just look what happened to Ivanpah? And the "wind off the coasts" projects rapidly sinking into the ocean floor muck as govts all over are pulling their plugs with the result of projects no longer making sense.
The good thing, however, is that there is a very much renewed look at nukes (utility, mid, and small sized units).
I live and work as an architect in Maine. We’re in the midst of a total exterior renovation and retrofit on our own home, adding 2” of rock wool, air barrier, new windows, and new cladding (windows and cladding were rotting). Also added overhangs and vented the roof. What confuses me is— I can’t see trying to heat an old, poorly insulated house with solely heat pumps in climate zone 6. I lived in my sister In law’s poorly insulated former “camp “ for a winter and we had to supplement the heat pump with a Rinnai propane fired heater when it got cold ($$$). The heat pump just didn’t cut it when it was below freezing. The houses around here that use only heat pump are new, super insulated houses (4” of continuous insulation, etc). We made the choice to go envelope first, partly to stop the deterioration of the structure. We figured we’d look at switching out our oil boiler and radiators at a later date. What am I missing?
I assume that you, being an architect, know how to perform a heat loss calculation (or know someone who does). It is summarized as a number in kW at a given design temperature outside.
Then just pick a heat pump that provides that power at that temperature.
In cold climates, it may be wise to have redundant, independent heating systems regardless the main technology (heatpump/wood/gas/oil).
Aside, just two inches of rockwool hardly counts as insulation in most places.
When doing a full renovation in a cold climate, consider hydronic underfloor/wall/ceiling heating. It is a perfect match with a A/W heat pump for high COP (but works just as well with gas/oil boilers) and improves the MRT directly for high comfort.
So much depends on the type of building and its condition. If it needs new windows and cladding, then consider adding some insulation - certainly air tighten the walls with a membrane. If it needs a new roof, upgrade the thermal performance at that time.
I've done analyses for century-old masonry bearing wall municipal buildings and concluded that insulating the walls doesn't make economic sense. I have a rough guideline for my area (New England, USA - hoping to become the next Canadian province) that I like to see the design load of a building get down to 20 BTU/hour/sf (63 W/m2) before converting to heat pumps.
In my online classes about decarbonization (Heatspring and Fine Homebuilding), I stress that when making these enclosure decisions it's important to identify all of the existing deficiencies that go beyond energy use. Is there mold? Water in the foundation? Pests? Recurring frozen pipes and ice dams? The value of thermal enclosure upgrades may be far more significant in rectifying these than in the energy saved.
Once the decision to convert to HPs is made, it's important to understand the real design load of the building. Fossil fuel systems are almost always oversized. We datalogged some of the aforementioned masonry municipal buildings during a very cold spell. They had existing NG heating systems sized at 50 BTU/hr/sf, our calcs showed 30, and actual peak was under 20. That saves a lot on heat pump costs, and also makes it easier to fit the new systems in the building.
I think focusing on insulation as the most important component of "fabric first" is a mistake. Airsealing is cheap and essential.
Some blower door operators give the usual report about airtightness in air changes per hour at 50 Pascal (---ach50) but also put airtightness in the form of how big a hole in the building envelope a given level is equivalent to. So "your house leaks like there's a 10cm x10cm hole in the outside wall" is a lot better than "your house leaks like there's a 50cm x 50cm hole in the wall."
True, air sealing can be cheap and relatively easy, but often comes with added expense of providing controlled ventilation.
"...Meeting this peak with renewables would require a 28× increase in January wind generation or a 303× increase in January solar, with excess generation in other months. Highly efficient building electrification can shrink this winter peak—requiring 4.5× more generation from wind and 36× more from solar."
No matter which increase is used, 28X/303X or the 4.5X/36X, that's a massive amount of land that will be required. And a HUGE CapEx in order to deploy. AND, to bring it home, the massively long timeframes to do all of the required studies to satisfy all of the policy statements/standards that (irony alert) have been put into force in govt by....environmentalists.
So, once again (heh - THE "evergreen" phrase for me over the years), WHO is going to pay the cost of either of the X increase sets, and WHO is going to have the money and time to go up against the entrenched NIMBY and BANANA eco-environmentalists that took the high ground years before in order to keep any of the needed building for those REs from happening.
And as to the cost, let's be blunt - you'll have to rely on eco-VCs to fork over the investment as this administration, and rightfully so (govt has almost ALWAYS proven to be a horrible VC due to political connections making the deals and not realistic ROIs). And those VCs are rather loathe to open up their piggybanks. Just look what happened to Ivanpah? And the "wind off the coasts" projects rapidly sinking into the ocean floor muck as govts all over are pulling their plugs with the result of projects no longer making sense.
The good thing, however, is that there is a very much renewed look at nukes (utility, mid, and small sized units).
Thank you for such a thoughtful take.
My own experience is that Conservation beats Consumption.
Also, I don't think that electrification is synonymous with de-carbonization.
That is a myth.
I live and work as an architect in Maine. We’re in the midst of a total exterior renovation and retrofit on our own home, adding 2” of rock wool, air barrier, new windows, and new cladding (windows and cladding were rotting). Also added overhangs and vented the roof. What confuses me is— I can’t see trying to heat an old, poorly insulated house with solely heat pumps in climate zone 6. I lived in my sister In law’s poorly insulated former “camp “ for a winter and we had to supplement the heat pump with a Rinnai propane fired heater when it got cold ($$$). The heat pump just didn’t cut it when it was below freezing. The houses around here that use only heat pump are new, super insulated houses (4” of continuous insulation, etc). We made the choice to go envelope first, partly to stop the deterioration of the structure. We figured we’d look at switching out our oil boiler and radiators at a later date. What am I missing?
I assume that you, being an architect, know how to perform a heat loss calculation (or know someone who does). It is summarized as a number in kW at a given design temperature outside.
Then just pick a heat pump that provides that power at that temperature.
In cold climates, it may be wise to have redundant, independent heating systems regardless the main technology (heatpump/wood/gas/oil).
Aside, just two inches of rockwool hardly counts as insulation in most places.
When doing a full renovation in a cold climate, consider hydronic underfloor/wall/ceiling heating. It is a perfect match with a A/W heat pump for high COP (but works just as well with gas/oil boilers) and improves the MRT directly for high comfort.