The order most homeowners do this in is backwards. They buy the heat pump, then the EV, then they are told the induction range needs a circuit, and only then does an electrician open the panel and deliver the bad news. Whole home electrification is a load problem before it is an equipment problem, and the load problem is answered in an afternoon if anyone asks it first.
This is the single most common conversation we are having with central Ohio homeowners right now, and the houses it bites hardest are the 1960s to 1990s builds across Hilliard, Gahanna and Grove City sitting on a service that was sized for a gas furnace, a gas water heater and one air conditioner.
What whole home electrification actually adds to the panel
Four loads do almost all of the damage, and they arrive one at a time over several years, which is exactly why nobody adds them up.
A cold climate heat pump replaces the air conditioner and the furnace. The compressor draws roughly what the old air conditioner did, so far so good. The problem is the supplemental electric heat that most installations carry for the coldest days. That element bank is often the largest single load in the house and it is the one people forget, because they think of it as the backup rather than as a load.
A Level 2 EV charger is a continuous load, which means it is calculated at 125 percent of its rating rather than at its rating. A charger that draws 40 amps is counted as 50.
An induction range replaces a gas appliance with a large 240 volt circuit that did not exist before.
A heat pump water heater is the mildest of the four, but it is another 240 volt circuit where a gas flue used to be, and pulling that water heater is what orphans the furnace on a shared chimney.
Add all four and a house that ran comfortably on a 100 amp service is asking for capacity it does not have.
Breaker positions and bus capacity are two different problems
This trips people up constantly. Running out of physical slots in the panel and running out of electrical capacity in the service are separate failures with separate fixes, and a contractor who conflates them will sell you the wrong job.
If the bus and the service are adequate but the panel is physically full, the fix can be a subpanel or, where the panel is listed for them, tandem breakers. Tandems are not universally permitted, the panel’s own label states how many the enclosure accepts and in which positions, and arc fault or ground fault requirements can rule them out for the circuits you actually want to add.
If the service itself is undersized, no amount of rearranging helps. That is a service upgrade: a new panel, usually a new meter socket, new service conductors, a utility coordination step and an inspection. It is a bigger job with a longer schedule, and it is the one worth knowing about before you order equipment. Our electrical panel service covers both cases, and the walkthrough that tells them apart is the same walkthrough either way.
The load calculation is the whole conversation
There are two recognised ways to answer this, and both are in the National Electrical Code. The standard calculation adds up connected loads and applies demand factors by category. The optional calculation for dwellings uses the largest heating or cooling load plus a percentage of everything else, and it usually gives a more realistic answer for a modern house because it accounts for the fact that the range, the dryer and the heat pump are rarely all at maximum together.
A third approach exists and is worth asking about: a calculation based on measured maximum demand from utility data over a defined period. Where a house has a long service history and the paperwork is available, that can show real headroom a paper calculation misses.
What matters is that somebody does one of the three, in writing, before equipment is ordered. A contractor who eyeballs the panel and says it will be fine is making your decision for you without doing the arithmetic.
Load management, the option most quotes leave out
If the calculation comes back short, a service upgrade is not automatically the answer. Load management hardware can let two large loads share one allocation by shedding or pausing one when the other runs. The common versions are a device that pauses EV charging when the dryer or the range is drawing, and a controller that sheds the heat pump’s supplemental heat before the service is stressed.
This matters because an EV charger and a heat pump almost never need full power at the same moment. The charger runs overnight, the supplemental heat runs on the coldest mornings, and even when they overlap, one can wait a few minutes. Whether it is the right call depends on the calculation and on the panel, but it belongs in the conversation rather than appearing after you have paid for a service upgrade you may not have needed.
Solar changes the arithmetic in a different direction
Adding solar to the picture is not simply more capacity. A backfed solar breaker adds current to the panel bus from the opposite end, and the Code limits the combination of the main breaker and the backfed breaker relative to the bus rating. The practical consequence is that a panel with just enough room for your loads may still not accept the solar breaker, and the answers are a supply side connection, a main breaker derate, or a panel change. Battery storage adds its own considerations because it is both a source and a load. Getting the panel decision right once, with solar and backup power on the table even if they are years away, is much cheaper than doing it twice.
What to ask before you buy equipment
Ask for the load calculation in writing, and ask which method was used.
Ask what the service size actually is, measured at the conductors and the meter, not read off the main breaker, because a 100 amp main on a panel does not prove the service conductors match it.
Ask whether the panel is listed for tandem breakers and in which positions, if that is the proposed fix.
Ask what the plan is for the loads you have not bought yet. If a heat pump is going in this year and an EV is likely in three, the panel decision should account for both now.
Ask who coordinates with the utility and what that adds to the schedule, because on a service upgrade that step, not the electrical work, is usually the long pole.
If you want that calculation done before you commit to equipment, start at the contact page. The heat pump and electrical departments do that walkthrough together, and the electrical side of a heat pump conversion is covered in more detail in our guide to converting from gas heat to a heat pump.
Frequently asked questions
Do I need a 200 amp service to add a heat pump and an EV charger?
Not necessarily, and the honest answer is that nobody can tell you without running the calculation for your house. Plenty of homes carry both on a 150 amp service, and some carry them on 100 amps with load management. What decides it is the supplemental heat bank on the heat pump, the charger rating, whether the range and dryer are gas or electric, and the square footage. Get the number before you get the quote.
My panel is full. Is that the same as my service being undersized?
No, and this is the most useful distinction in the whole subject. A full panel is a physical problem: no positions left. An undersized service is an electrical problem: not enough capacity coming into the house. A full panel with adequate capacity is often solved with a subpanel or, where the panel is listed for them, tandem breakers. An undersized service needs new conductors, usually a new meter socket, and utility coordination.
Can I add an EV charger without upgrading my electrical service?
Frequently yes. A charger can be set to a lower current than its maximum, which reduces the calculated load, and load management hardware can let the charger share capacity with another large appliance by pausing while that appliance runs. Overnight charging rarely needs the full rating. This is worth exploring before committing to a service upgrade.
Will adding solar give my panel more room for new loads?
It does not work that way. Solar is a source, not spare capacity, and a backfed solar breaker actually consumes room in the panel because the Code limits the main breaker and the backfed breaker together against the bus rating. A panel that just fits your loads may still not accept the solar breaker. If solar is anywhere in your plans, say so before the panel decision is made rather than after.
How long does an electrical service upgrade take?
The electrical work itself is usually a day. The schedule is set by everything around it: the permit, the utility coordination for the disconnect and reconnect, the meter socket, and the inspection that has to happen before power is restored. Ask for the sequence rather than the labour time, because the labour time is the smallest part of the answer.