MotherMayI
08-08-2010, 03:06 AM
In 10 days, Spouse and I will become owners of a rad-heated house in Toronto that lacks air conditioning and mechanical ventilation. Before we seek proposals and quotes from local HVAC contractors, we would like to find out what the professionals on HVAC-TALK think would be good possible approaches.
Here are some details. I hope they're useful.
It's a two-storey brick house built in 1935. There's a wood-burning fireplace in the basement & another above it in the living room. The original heating system is hot-water rads; the gas boiler in the basement was replaced 7 or 8 years ago. There's a range hood in the kitchen. The current water heater, stove/oven and clothes dryer are all electric.
The current owner bought the house in 2007 and renovated it over the next several months, but he has never lived there; in fact, no one has lived there since he bought it.
The renovations include the following:
1) a solar water-heating system, with panels on the roof of the detached garage, to supplement the hydronic system;
2) radiant in-floor heating in one room on the second floor and two on the ground floor;
3) mechanical ventilation in all the bathrooms (the original plus the three he added, one on each level);
4) all new rads;
5) the extension he added along the back and a verandah along the front and part of one side required him to remove several windows from the basement; there remain 2 windows, small but above grade, on one wall of the basement;
6) all the windows are, according to the owner, "energy-star certified by manufacturer with cement board as sills, and mortar-filled grout";
7) the exterior doors were replaced with insulated doors;
8) for the exterior walls, the owner added insulation that, he claims, meets R2000 standards ("2 layers of vapour barrier: one is the tyvex paper covering behind the brick and then the vapour barrier 6 mil," the owner writes. "The insulation is R 40 in ceiling and R 20-6 inch in walls with studs. all barriers are sealed tight with tuck tapes”);
9) he made the ground floor open concept; the staircase does stand almost in the middle, the nearest thing there is to a wall between dining and living rooms);
10) he made the basement one big room and open to the main floor;
11) he turned the four-bedroom, one-bathroom second floor into three bedrooms and two bathrooms.
Other notes:
-The home inspector says the attic insulation is R-20 but should be increased to R-40.
-There is only one closet on the second floor that runs floor to ceiling; the rest are small, short spaces tucked into the walls around dormer windows. The landing at the top of the stairs is not spacious. In any case, my husband and I would rather not have any ducts, however mini, to run through the second storey to the first.
-the basement and second floor are roughly 930 sq ft each, but the ground floor is about 1250 sq ft, thanks to the extension.
What would the members of the forum suggest for such a house by way of A/C and mechanical ventilation?
Do we need an HRV system? ERV? Just plain old mechanical ventilation to get air exchanges happening? How would it work over the whole house without ducts? Is it possible to have whole-house ventilation of any kind without running ducts from the attic down to the first floor? Can separate floors have separate ventilation systems? If so, would the basement get its own system, too?
Is it feasible/practical to have an attic-based high-velocity system only for the second floor, and then a small number of strategically-placed ductless mini-split wall units on the main floor?
How would an added A/C system work with an added ventilation system? Can they share mini-ducts?
Should we do something to the wood-burning fireplaces? Seal them? Replace them? Use them as they are? Are HVAC contractors the appropriate people to ask about this?
Finally, some questions about working with the contractors we ask to prepare quotes (we're going to ask four companies):
1) should we ask the HVAC contractors to do a load calculation? Or should we just ask for their ideas and quotes?
2) Should we settle on a solution and then invite quotes? Or should we let the contractors pitch different ideas as well as quotes (in which case, how do we compare them?)?
If I should break this whole thing up into different threads or different sub-forums, please let me know.
Thank you for your patience in reading this and time spent thinking about this.
Here are some details. I hope they're useful.
It's a two-storey brick house built in 1935. There's a wood-burning fireplace in the basement & another above it in the living room. The original heating system is hot-water rads; the gas boiler in the basement was replaced 7 or 8 years ago. There's a range hood in the kitchen. The current water heater, stove/oven and clothes dryer are all electric.
The current owner bought the house in 2007 and renovated it over the next several months, but he has never lived there; in fact, no one has lived there since he bought it.
The renovations include the following:
1) a solar water-heating system, with panels on the roof of the detached garage, to supplement the hydronic system;
2) radiant in-floor heating in one room on the second floor and two on the ground floor;
3) mechanical ventilation in all the bathrooms (the original plus the three he added, one on each level);
4) all new rads;
5) the extension he added along the back and a verandah along the front and part of one side required him to remove several windows from the basement; there remain 2 windows, small but above grade, on one wall of the basement;
6) all the windows are, according to the owner, "energy-star certified by manufacturer with cement board as sills, and mortar-filled grout";
7) the exterior doors were replaced with insulated doors;
8) for the exterior walls, the owner added insulation that, he claims, meets R2000 standards ("2 layers of vapour barrier: one is the tyvex paper covering behind the brick and then the vapour barrier 6 mil," the owner writes. "The insulation is R 40 in ceiling and R 20-6 inch in walls with studs. all barriers are sealed tight with tuck tapes”);
9) he made the ground floor open concept; the staircase does stand almost in the middle, the nearest thing there is to a wall between dining and living rooms);
10) he made the basement one big room and open to the main floor;
11) he turned the four-bedroom, one-bathroom second floor into three bedrooms and two bathrooms.
Other notes:
-The home inspector says the attic insulation is R-20 but should be increased to R-40.
-There is only one closet on the second floor that runs floor to ceiling; the rest are small, short spaces tucked into the walls around dormer windows. The landing at the top of the stairs is not spacious. In any case, my husband and I would rather not have any ducts, however mini, to run through the second storey to the first.
-the basement and second floor are roughly 930 sq ft each, but the ground floor is about 1250 sq ft, thanks to the extension.
What would the members of the forum suggest for such a house by way of A/C and mechanical ventilation?
Do we need an HRV system? ERV? Just plain old mechanical ventilation to get air exchanges happening? How would it work over the whole house without ducts? Is it possible to have whole-house ventilation of any kind without running ducts from the attic down to the first floor? Can separate floors have separate ventilation systems? If so, would the basement get its own system, too?
Is it feasible/practical to have an attic-based high-velocity system only for the second floor, and then a small number of strategically-placed ductless mini-split wall units on the main floor?
How would an added A/C system work with an added ventilation system? Can they share mini-ducts?
Should we do something to the wood-burning fireplaces? Seal them? Replace them? Use them as they are? Are HVAC contractors the appropriate people to ask about this?
Finally, some questions about working with the contractors we ask to prepare quotes (we're going to ask four companies):
1) should we ask the HVAC contractors to do a load calculation? Or should we just ask for their ideas and quotes?
2) Should we settle on a solution and then invite quotes? Or should we let the contractors pitch different ideas as well as quotes (in which case, how do we compare them?)?
If I should break this whole thing up into different threads or different sub-forums, please let me know.
Thank you for your patience in reading this and time spent thinking about this.