Adding air conditioning to the house

[tractng]

Hello,

My GF current house has heating but no AC. The heating unit is about 27 years old. So far we got one estimate to replace the entire system including new duct work. My concern is the current power panel is 100 amps.

The technician said he could pull the current circuit breakers and use the slim versions to add the breakers for the AC. The stove in the house is also electric . From the attached pictures, what are those breakers type called? Its older than dirt.


Thanks,
TT

 

[Sparky617]

What brand is your panel? You'd have to do a load calculation to know if you could add AC to that panel. I suspect you're in need of an upgrade to a 200 amp panel. Electrical panel manufacturers make slim breakers that will put two 15 or 20 amp circuits in the space currently occupied by one breaker. Some make a breaker for two circuits that fit in that space rather than slim breakers. In today's world 100 services are undersized for most homes modern needs. Though appliances and lighting are much more efficient these days we tend to have more of them.

Back in the day when 60 and 100 amp appliances were dominate we didn't have electric clothes dryers, 65" TVs, multiple TVs, multiple computers, DVR/Set Top boxes, microwaves, Keurig machines, routers, printers, etc. all drawing power. My two central AC units draw 240v 20a and 240v 25a, the range circuit is a 50 amp. Dryers are 240v 30a. Kitchen and bath circuits are 20a. It is easy to see you could be doing a load in the dryer, while running the stove, microwave, with a TV on, several computers and have the AC kick on. Oh and probably in the next 10 years you'll likely have at least one electric car.

 

[Sparky617]

Back in the day when 60 and 100 amp appliances services were dominate.

 

[tractng]

I believe it is a GE panel. I am not there at the moment.

 

[Sparky617]

I haven't worked as an electrician, though I did study to be one decades ago. I think you're pushing the limit of your panel if you want to add HVAC I think a service upgrade to 200a and a new panel are going to be required. Running your dryer, range, water heater, AC along with all the other stuff in your house will reach the 100a capacity of your service. Skinny breakers are available for GE panels, but I think you're running out of amperage capacity.

 

[user 4883]

Hello,

My GF current house has heating but no AC. The heating unit is about 27 years old. So far we got one estimate to replace the entire system including new duct work. My concern is the current power panel is 100 amps.

The technician said he could pull the current circuit breakers and use the slim versions to add the breakers for the AC. The stove in the house is also electric . From the attached pictures, what are those breakers type called? Its older than dirt.


Thanks,
TT

What are the 3 2-pole breakers for on the right?
Was wondering if you have electric heat or gas.

 

[Sparky617]

What are the 3 2-pole breakers for on the right?
Was wondering if you have electric heat or gas.

We know one is the range, I'd guess water heater is one, and dryer is the other. If there is gas the water heater might be gas. Dryer could be gas, but not as likely.

 

[user 4883]

We know one is the range, I'd guess water heater is one, and dryer is the other. If there is gas the water heater might be gas. Dryer could be gas, but not as likely.

replace the electric appliances with gas and you'll have plenty of room for an upgrade to AC.

 

[Sparky617]

replace the electric appliances with gas and you'll have plenty of room for an upgrade to AC.

For a modern home, a 100 amp service is pretty small. Electric cars will be a part of our lives in the next 10 years. I'd upgrade the panel and the service to 200amp while I was adding HVAC. We don't know the location, nor do we know if the house has gas available. If no gas, and not too far north I'd probably opt for a new high efficient heat pump. If far north I'd opt for a ground sourced heat pump if there wasn't gas available.