HVAC design for a Clarington building permit
Clarington is not one of the municipalities listed in SB-1, so the outdoor design temperature for your calculation is not a number you can simply look up. Here is how that is properly resolved, and what Clarington asks for with a permit application.
Clarington is not listed in SB-1 — here is what that means
Supplementary Standard SB-1 does not list every Ontario municipality, and Clarington is one it leaves out. SB-1 says so itself: “As it is not practical to list values for all municipalities in Ontario”, and directs you to Environment and Climate Change Canada for a recommended value for an unlisted location.
What you must not do is use the nearest town’s number. SB-1 contains no “nearest location” provision and warns that interpolating to other locations may not be valid because of local effects.
Clarington spans more than one SB-1 row — its own snow-load bulletin cites both Newcastle and Newcastle (Bowmanville). It cannot carry one design temperature.
What to do instead, in order:
- Ask the building department which row they expect you to use. Some municipalities publish this — Clearview and The Blue Mountains both direct designers to the Collingwood row in writing, which makes it a sourced value rather than a guess.
- If they have no position, request a value from Environment and Climate Change Canada’s Engineering Climate Services Unit, as SB-1 instructs.
We do this as part of every job in an unlisted municipality, and we put the source of the figure we used on the assumptions page so your reviewer can see it.
Source: Ontario Building Code SB-1 (2024), Table 2 — Climatic Design Data.
What each document actually is
| Document | What it is |
|---|---|
| Heat loss and heat gain calculations | The room-by-room load. Everything else is sized off this. |
| Formula sheet | The working behind the numbers, so a reviewer can follow them. |
| Thermal load calculator | The envelope assemblies and areas the loads were built from. |
| Air leakage calculator | The infiltration assumption, stated rather than buried. |
| Residential ventilation summary | The OBC 9.32 ventilation design, on the HRAI summary form. |
| Duct design and layout | Supply and return sizing, register locations, cfm per room. |
| Energy Efficiency Design Summary | How the house meets SB-12, prescriptive or performance. |
| Radiant in-floor design | Loop layout, spacing, manifolds and lengths. |
| Hydraulic load calculations | Flow and head for a hydronic system. |
Who is allowed to sign it
You hire a qualified designer. They complete the Schedule 1 Designer Information Form with their BCIN and take responsibility for the design.
You are the owner, building on your own lot. Ontario Building Code Division C, Article 3.2.5.1.(3)(b)(i) exempts an owner who designs a house they own from the designer qualification requirements. You can file the documents yourself. The calculations still have to be correct — the exemption is about who may design, not about the standard the work has to meet.
Tell us which applies and we will tell you what you need before you pay.
What it costs
| Includes | Price | Turnaround | |
|---|---|---|---|
| Heat loss and heat gain | Room-by-room loads, worksheet, design conditions, equipment sizing basis, assumptions, seal page | $395 | 48 hours |
| Full mechanical package | The above plus ventilation design, duct design and layout, EEDS, and radiant layout where applicable | $695 | 48 hours |
Forty-eight hours from complete plans and payment. If the building department asks for a correction to something we got wrong, we fix it and reissue at no charge while your application is open.
See a complete sample package →
Common questions
Do I need all of these documents? Not always. A heat loss calculation alone satisfies some permits; a new dwelling with a hydronic system needs close to the full list. Send the plans and we will tell you which.
The department has already asked and my build is held up. That is the most common reason people call. The 48-hour turnaround exists for exactly that.
My HVAC contractor says he will size it. He may be right about the equipment. The building department still needs the documents, and the Code requires equipment capacity to be based on the calculated design heat loss.
I’m adding a basement apartment, not building a house. Different job: no drawings, an existing furnace, and a check that it can carry both units. Here is how that works → The design temperature and the checklist above apply to it just the same.
Does an ICF or high-performance house change the answer? Same procedure, different inputs. The result usually comes out substantially lower, and more of the difference comes from air sealing than from the wall’s R-value. We run that comparison on every job.
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Send your plans — we’ll tell you what you need before you pay →