http://www.geocities.com/torontotenants/law/law.html#Q7
Q7: My apartment is too cold. What must the landlord provide?
A7: The temperatures are set under municipal bylaws. If you are not the cause for the cold temperatures, such as by keeping your windows open, or setting a thermostat to a lower temperature, then the landlord has a responsibility to maintain a minimum temperature as set by the municipality/city you live in. If the landlord is not meeting the minimums, you can complain to the city's Building and Inspections department or your city councillor.
Information for some cities and towns are:
In Barrie it is 20C (68F) year round under their bylaw #84-200
Belleville is 21C (70F) from September 15 to May 31 under they bylaw 2000-45
Brampton is 20C (68F) from September 15 to June 1. Brampton Heat Bylaw
Cornwall is 21C by day and 16C by night, from Oct. 1 to April 30, with no definition of day or night, under Section 2.35, Heating System, of the Property Standards By-law. If these requirements are not being met you may call for a Property Standards Inspector (613) 930-2787.
Guelph is 21C (70F). If it isn't warm enough call the Building Dept. Property Standards at (519) 837-5615
Hamilton is 22C (72F)
Kingston is 21.1C (70F) from 6:00 a.m. to 11:00 p.m. and 18.8C (66F) the rest of the day from September 15 to June 1, see their by-law in Microsoft Word format
Kitchener is 21C (70F) year round under their bylaws for Property Maintenance, chapter 640.
London is 20C (68F) from 6:00 a.m. to 11:00 p.m. and 18C (65F) the rest of the day from September 15 to June 15, under the City of London, Vital Services By-law PH-6, section 3.4
In Mississauga it is 20C (68F) from September 15 to June 1. Mississauga Heat Bylaw
In Niagara Falls it is 21C (70F) from September 15 to May 31 under By-Law 98-50.
In North Bay it is 21C (70F) year round. North Bay' bylaw in Adobe format
Oakville is 21C (70F). If it is not warm enough call the Halton Environmental Health office at (905) 825-6000.
Oshawa is 20C (68F) from September 15 to June 15.
Ottawa is 20C (68F) from 6:00 a.m. to 11 p.m., and 16.7C (62F) from 11:00 p.m. to 6:00 a.m., year round, under (Old City of) Ottawa By-law #201-89. If your apartment is too cold in Ottawa, the number to call is (613) 580-2400.
Peterborough is 21C (70F) Property Standards - go to Chapter 611.9.1 (Adobe PDF document)
Richmond Hill is 20C year round.
Sarnia is 21C by day and 18C by night (from 11:01p.m. to 6:00 a.m.) under bylaw 16 of 1994.
Sault Ste. Marie under bylaw 3627 is 20C (68F) year round.
St. Catharines is 20C from September 15 to May 31 under By-law #66-48 "A By-law to require adequate heat for rented dwelling accomocadation" from 1966 and amended in 1983
Sudbury is 21C (70F) year round, under By-law #2001-200.
Thunder Bay it is 21C (70F) year round. To see the bylaw, hit "continue" at the bottom of that page
Timmins is 21C (70F) year round under Section 2.7 of the Maintenance and Occupancy By-Law 98-5118.
Waterloo is 21C (70F) under the Heating Systems section of the Property Standards By-law 94-16 If there is not sufficient heat you can call Standards enforcement at (519) 747-8557, or contact your City Councillor.
Windsor is 21.11C (70F) from September 15 to June 15 under by-law 1152.
If you need to contact your city/town or your city councillor about this you can find their web page at my Government home pages
In Toronto the temperature must be a minimum of 21C (70 Fahrenheit) from September 15 to June 1. The numbers to call are:
Old City of Toronto - (416) 392-0381 and 338-0338 (Access Toronto)
East York - (416) 397-4590
Etobicoke - (416) 394-8055
North York - (416) 395-7000
Scarborough - (416) 396-7322
York (old city of) - (416) 394-2490
(Source: City of Toronto, Telephone Directory, January 2001, Directory of Services, page 273)