Plumber or electrician needed, If I have replaced the heating elements in an old water heater?

New heating elements won't improve the energy efficiency of an electric hot water heater.

More insulation will. You can get insulation blankets designed to wrap around a hot water heater for very little money. They are easy to install.

35 years on a water heater is amazing. Usually they start leaking at about 15 years or less.

A plumber can replace the heating element(s). Even a DIY can do it.

But anyway, if it isn't leaking, just replace the element(s) as needed. Most water heaters I know of already have an insulation blanket around the tank. It still takes a fixed amount of energy (BTUs) to heat 50 gals of water to a specified temperature. Modern heaters can heat that water faster, but still takes the same amount of energy.

Efficiency goes up when you use a heat pump or solar energy to heat the water. But these systems come with a higher initial cost.

The immersion heating element in an electric water heater of any age is nigh on 100% efficient, because wasted energy only escapes into the water heater, ie helping with the heating. Even the small amount of heat that escapes from the end (where the electricity supply is attatched) is only wasted in summer when you are not heating your home. You could make some energy savings by upgrading the whole heater to something different or fit more insulation to the existing unit. The best option depends on your hour water usage profile, which also applies to using a timer to control the element.

First of all, Congrats on 35 YEARS!

It must be maintained really well.

It might not be as efficient as if it was new, but as long as it's doing its job, and have no leaks, it would be worth to keep than getting a new one as long as the heating elements aren't changed every 5 years. Hope water heater is drained periodically and properly. If the water inside is empty and the unit is on, the heating elements will seize immediately. I'd also check if cold water inlet isn't bent or clogged.

Newer heating elements are more efficient than old residue accumulated elements.

Have you ever checked the circuit breaker to make sure that it is not tripped?When you've got power then there's simplest three things it might be the thermostat, plugged give pipes or your water heater is absolutely filled with agreement.When you get water while you activate the hot water faucet then we are able to rule out plugged pipes.I might say then that you simply should have your thermostat checked out. And expectantly the water heater isn't filled with agreement however you might assess that through opening the drain valve placed toward the backside of the unit.If that's k it will just about need to be the thermostat.If all else fails you'll must change.Take care and may just God bless you.

No, it doesnt increase the energy rating