Short answer: maybe, and you can usually tell which way it will go in an afternoon. Floor space is almost never the problem. Power and cooling are.
If you own or manage a building in Ontario and someone has asked whether a room can host GPU servers, or you are wondering whether a colocation business is worth starting, this is the order I would check things in. Each check can end the conversation. Do the cheap ones first.
All dollar figures below are Canadian unless marked US. Prices and assumptions are dated November 2026. They are examples to show the arithmetic, not quotes.
1. Power: find the all-in rate and the spare capacity
Two numbers decide whether the power side works: what a kilowatt-hour really costs you, and how many kilowatts the building can still give.
The all-in rate. An Ontario commercial bill has a commodity charge, a global adjustment, delivery, regulatory charges and, for larger customers, demand charges. The rate printed on the front is not the rate you pay.
The global adjustment is the volatile part. The IESO’s 2025 Year in Review shows how much it moves. The Class B global adjustment averaged 7.01 cents per kWh in 2024 and 4.56 cents in 2025. The commodity price moved the other way, from 3.37 cents to 6.41 cents. The IESO also notes that the Hourly Ontario Energy Price ended on May 1, 2025 and was replaced by the Ontario Price, so the 2025 figure blends two pricing systems. The total commodity-plus-adjustment cost for Class B was 10.38 cents in 2024 and 10.96 cents in 2025. That total still excludes delivery and demand charges.
The IESO also publishes the monthly Class B rate, which can swing a lot from one month to the next. Do not build a model on one month’s bill.
Larger customers may be able to choose Class A. Under the Industrial Conservation Initiative, a Class A customer pays global adjustment based on its share of demand during the five highest Ontario demand hours of the base period, not per kWh. Hydro One’s page, checked November 11, 2026, lists eligibility starting above 500 kW of average monthly peak demand, with some restrictions below 1,000 kW. That is a big load for a small room, but it matters if the building as a whole is large.
What to pull from 12 months of bills. Get twelve consecutive months for the meter that would feed the room, and write down:
- total dollars before HST, and total kWh, for each month;
- the billed peak demand in kW for each month, if you have a demand charge;
- the size of the electrical service (amps, voltage, phases) and what else is on it.
Divide total dollars by total kWh over the twelve months. That is your all-in rate. A rate near 15 cents per kWh is a reasonable number to test with. I use C$0.15 per kWh in the arithmetic below. Yours may be different, and that is the point of pulling the bills.
Subtract your highest monthly peak demand from the service capacity. What is left is the headroom, before any safety margin. Then ask your local distribution company in writing how much capacity is available at your connection point, what an upgrade costs and how long it takes. The wait for a service upgrade is often longer than the wait for the hardware.
2. Power per rack: why a legacy rack is not a GPU rack
A legacy rack in an older room was often designed for roughly 5 to 10 kW. That is consistent with the Uptime Institute’s 2026 survey, as reported by Data Center Knowledge, which put the average rack at 7.8 kW and the most commonly reported density at 11 kW.
Modern GPU hardware does not fit that picture:
- One NVIDIA DGX B200 system is rated at about 14.3 kW maximum and takes 10 rack units, per NVIDIA’s product page (checked November 11, 2026). One box, with eight GPUs, is already more than a whole 10 kW legacy rack.
- An NVIDIA RTX PRO 6000 Blackwell card is rated at up to 600 W, per NVIDIA. A four-GPU server built on those cards is about 2.4 kW of GPU plus the rest of the machine, so roughly 3 kW at full load. I treat that as an estimate and check the vendor’s spec sheet for the actual server.
- At the top end, NVIDIA’s GB200 NVL72 is a liquid-cooled rack of about 120 kW, per NVIDIA’s OCP contribution and its DGX GB user guide. That is not a building-retrofit conversation. It is a purpose-built data hall.
For an ordinary older Ontario room, the realistic target is the small end: a few four-GPU servers per rack, at 6 to 12 kW per rack.
Here is the electrical arithmetic for a room of five racks at 9 kW each, which is three of those four-GPU servers per rack. This is an example to show the method:
- IT load: 5 racks x 9 kW = 45 kW.
- With cooling and distribution overhead of about 30 percent (a PUE of 1.3), the building feels 45 x 1.3 = 58.5 kW.
- On a 208 V three-phase supply, current is 58,500 W / (1.732 x 208 V) = about 162 A, before the margin your electrician is required to add for continuous loads.
If your spare capacity is 60 A, the answer is already no-go, or it is a service upgrade project. If it is 400 A, you are fine on this check.
3. Cooling: the hardest constraint in an older room
Every watt that goes into a server comes out as heat. One kW of IT load is about 3,412 BTU per hour. One ton of cooling is 12,000 BTU per hour, or about 3.5 kW.
So the 45 kW room above needs about 45 / 3.5 = 12.8 tons of cooling that runs all year, including in January, at night and on a long weekend. The office air conditioner that handles the building’s occupants will not cover it.
The mistake I see is checking tons and stopping. Three other questions matter:
- Can the cooling reach the rack? Air has to move to the front of the servers and the hot exhaust has to go somewhere that is not the intake. A ceiling-return office room with a few floor diffusers mixes hot and cold air, and the servers at the top of the rack overheat first.
- Where does the heat go? A rooftop unit, a chilled water loop or a dry cooler outdoors all need space, structural support and, in many cases, a permit.
- What is the failure mode? If the cooling stops, a dense room heats quickly. Ask what happens at 3 a.m. on a Sunday and who gets the alarm.
If your mechanical engineer says the existing system cannot carry the load, price the new system before you price anything else. It is often the line that decides the project. At rack densities above what air can carry, you are into liquid cooling, which is a different building.
4. Fiber: two paths, not two bills
GPU inference and storage traffic need dependable connectivity, and tenants will ask about it first.
- How many carriers can serve the address, and what do they quote for a dedicated circuit?
- Do two carriers actually mean two physical paths? Two providers can share one conduit, one pole line or one building entrance. Ask for route maps and where each cable enters the building.
- Is there space in the building for a meet-me room or at least a demarcation point that a tenant can reach?
Diverse fiber at the street is a minimum. Diverse fiber into the building is the real answer. Quotes and install times vary widely by address, and some carriers will not build to a location without a commitment. Ask early.
5. Revenue-grade metering, if you will bill for power
If you intend to bill tenants for the electricity they use, the meter becomes a legal question, not just a technical one.
Measurement Canada, the federal regulator for trade measurement, says in its bulletin on revenue meters (published July 22, 2013, last modified February 4, 2020) that any metering device used to establish the basis of a charge for electricity is a revenue meter. It includes sub-metering devices used to determine charges for individual purchasers in a multiple-unit complex. Devices used only for non-billing purposes such as load monitoring are not revenue meters, as long as no charges are directly established from their readings.
In practice that means: a meter that decides what a tenant is billed is probably a revenue meter, and revenue meters have approval, verification and sealing requirements. A cheap monitoring meter from a PDU vendor is not the same thing.
I am not a lawyer and this is the part where I stop. Before you quote a per-kWh price to anyone, confirm with Measurement Canada, the Ontario Energy Board and your lawyer what applies to your setup. One way to avoid the question is to bill a fixed capacity fee per kW and not bill from meter readings at all. That is a contract and metering design choice, not a loophole, so get it checked.
6. Generator and fire suppression
Neither is exotic, and both can cost more than people expect.
Backup power. Do your tenants need to stay up through an outage? If yes, you need a UPS for the ride-through and a standby generator for anything longer. Ask what the generator is sized for (the whole building or just the room), how long the fuel lasts, how often it is tested under load and who can install it. Also ask your municipality and your insurer what approvals a standby generator needs at your address. A diesel generator next to a residential neighbour can be a zoning conversation.
Fire. A room full of high-density electrical equipment is a different fire risk than an office. Find out what suppression the room has today, and who the authority having jurisdiction is, normally your local fire department and your insurer. NFPA publishes NFPA 75 on fire protection for IT equipment and NFPA 2001 on clean agent systems. A conventional wet sprinkler over live servers is a common finding in an older room, and replacing it is a real project.
Tell your insurer before you sign anything. Some policies exclude or reprice this use, and it is much cheaper to learn that now.
7. The economics: hardware dominates, power does not
Owners tend to ask about electricity first. At small scale, it is the smallest line.
Take one four-GPU server, an RTX PRO 6000 class machine at about C$115,000 all-in. That price is my assumption for November 2026, not a quote. Amortize it over 36 months:
- Hardware: $115,000 / 36 = about $3,194 per month.
- Power, at the all-in rate of C$0.15 per kWh, and an average IT draw of about 2 kW at moderate utilization, which is about 2.64 kW at the building’s meter with a PUE of 1.3: 2.64 kW x 730 hours x $0.15 = about $289 per month.
Power is about 8 percent of those two lines ($289 of $3,483). For the same server at full load of 3 kW around the clock:
- 3 kW x 1.3 x 730 x $0.15 = about $427 per month, or 12 percent of the total.
Now scale it to a rack with three of those servers at 9 kW:
| Line (per month) | Calculation | Amount |
|---|---|---|
| Hardware amortization | 3 x $3,194 | $9,583 |
| Power at full load | 9 kW x 1.3 x 730 x $0.15 | $1,281 |
| Power share | $1,281 / ($9,583 + $1,281) | 12% |
Three observations from that table:
- If you are the building owner and the tenant owns the hardware, your costs are power, cooling, space and your capital for the upgrades. Your revenue has to cover the power at the all-in rate first, then the cooling plant, then the rest. A tenant paying a space fee with power at cost shifts the risk of a rate spike to the tenant. A tenant paying a flat fee shifts it to you.
- If you are the operator and own the hardware, your biggest risk is not the power bill. It is utilization. Hardware amortization runs whether the GPUs are busy or not, so an idle server costs nearly the same as a busy one.
- A swing in the global adjustment moves the power line by a few percent of the total, not the whole business. A swing in utilization moves the whole business.
For the same arithmetic applied to what a private AI deployment costs per user, see should we buy GPUs or keep paying for Copilot. For the larger, financed version, see what does it actually cost to run a GPU cluster.
Common questions
How much power does a rack of GPU servers need? For small deployments built on cards like the RTX PRO 6000 (up to 600 W each), plan on roughly 6 to 12 kW per rack, about 3 kW per four-GPU server at full load. An eight-GPU DGX B200 system is rated at about 14.3 kW by itself. A GB200 NVL72 rack is about 120 kW and liquid cooled. Check the exact server’s specification sheet.
Can an old office building host GPU servers? Sometimes. It passes if the electrical service has spare capacity, the room can be cooled around the clock, and the fire protection can be upgraded. Cooling and electrical capacity are what usually decide it, not floor area. Start with the twelve months of bills and the service size.
What is the all-in electricity rate for a commercial building in Ontario? It depends on your account, so calculate yours: total dollars before HST divided by total kWh, over twelve months. For context, the IESO reports the Class B commodity and global adjustment portion together at 10.96 cents per kWh for 2025, and that excludes delivery and demand charges.
Can I bill tenants for electricity? Possibly, but a meter used to set the charge is a revenue meter under Measurement Canada’s rules, and there may be Ontario rules on top. Confirm with Measurement Canada, the OEB and your lawyer before quoting a price.
Is power the biggest cost of hosting GPUs? No. In the example above, hardware amortization is 88 to 92 percent of the monthly cost of a four-GPU server, and power is 8 to 12 percent. Utilization matters more than the electricity rate.
How long does it take to find out if my room is viable? The first screen is a few hours: the bills, the service size, the cooling system’s capacity and a look at the room. That is the scope of the quick assessment described at the end of this post.
What to do next
If you work through the seven checks and the answer is still maybe, the next step is a walk through the room with someone who has seen these rooms before. I do that as a fixed-fee compute site readiness review: a one-hour quick assessment with a one-page go or no-go memo, or a full review with a cost model per rack and per GPU. The electrical, mechanical and fire work itself still belongs to licensed trades and engineers. What I give you is the decision, the numbers behind it and the risks to price before you spend money on drawings.