YANKTON,S.D.(WNAX)- The coldest air of the winter will arrive this weekend, dropping low temperatures to twenty below zero and possibly colder.

That will put a strain on home heating equipment and costs.

Tom Glanzer with Northwestern Energy says it took a while for the chill to get here.

Glanzer says there is a balance between heating your home and avoiding a soaring bill.

Glanzer says people should watch the intake and exhaust vents on their homes.

Glanzer says they have plenty of natural gas supplies to ride out the cold wave.