ARU calculator: rent, grants and payback

How the ARU calculator works

It subtracts any local grant or forgivable loan from your project cost, then divides by the yearly rent after your costs and a 3% vacancy allowance. When a program caps rent, it uses the lower of your market rent and the cap, so you can see what the incentive really costs you.

• Kingston: lesser of 50% or $40,000 (detached) or $30,000 (interior), with rent capped at 90% of average market rent for 5 years.
• Belleville: $5,000 rebate per ADU ($10,000 for a third), no rent cap.
• Cobourg: Northumberland County up to $20,000 with 25 years of capped rent.

Programs change and some are waitlisted. Check the details in each city guide and our secondary suite financing guide. Not sure your lot qualifies? Try the what can I build checker. This is an estimate, not financial advice.

Frequently asked questions

How long does a secondary unit take to pay for itself?

Divide what the unit costs you, after any grant, by the rent it earns each year after expenses. A unit that nets $15,000 a year on $150,000 of cost pays back in about 10 years, before financing costs and before any rise in property value.

Is a forgivable loan worth the rent cap?

Compare the loan with the rent you give up. If market rent is close to the capped rent, the loan is almost free money. If market rent is far above the cap, five years of the difference can exceed the loan. The calculator shows both sides.

Does this include mortgage interest?

No. It is a simple cash payback estimate. If you finance the build, for example with a CMHC-insured refinance, add the interest to your monthly costs to see a fuller picture, and talk to your lender or accountant.