A Purdue University field test could challenge one of the biggest assumptions surrounding residential electrification:
That installing heat pumps and electric water heating necessarily requires a major electrical-service upgrade.
Researchers operated a fully electrified 1920s home for 31 consecutive winter days while keeping electrical demand within the limits of a 100-amp panel.
Temperatures fell as low as -4°F during the test.
The system managed electrical demand primarily by making small adjustments to two appliances:
the heat pump,
and the water heater.
Under conventional electrical-code load calculations, the same house would nominally require a 200-amp service.
Why This Matters for HVAC Contractors
Electrical capacity is increasingly becoming an HVAC sales problem.
A homeowner may be willing to install a heat pump.
But if the project suddenly also requires:
a new panel,
utility work,
new service conductors,
and thousands of dollars of electrical upgrades,
the economics can change quickly.
That can stop an otherwise viable HVAC project.
Load-management systems offer another possibility.
Instead of increasing the maximum amount of electricity available to the house, software coordinates when high-demand appliances operate.
The Contractor Opportunity
If systems like this become commercially scalable, HVAC contractors could find themselves increasingly working alongside electrical contractors on managed-load retrofits rather than conventional panel upgrades.
That could reduce project cost and make electrification practical in a much larger portion of America's older housing stock.
The field test does not establish that every 100-amp home can avoid an upgrade.
Loads, climate, appliances and local codes vary significantly.
But it challenges a powerful assumption.
The answer to more electric equipment may not always be a bigger electrical service.
Sometimes it may be smarter control of the service already there.
