can heat pumps increase heating costs?

It depends. Heat pumps are just like air conditioners but with one difference they can be reversed. With air conditioners they move heat from inside your house to outside and that is all. Heat pumps have a little bit more plumbing and a "reversing valve". That extra design and parts allow the heat pump to move heat from inside your house AND they can move heat from outside your house to the inside.

If your using a geothermal based heat pump then it won't increase heating cost compared to electric heat but if it is an "air exchange" heat pump then only when the outside temperatures get very cold outside will it cost more . 40 or 45 deg. f is about where it changes. The colder the air is outside the more it costs to move heat from outside to inside. They usually switch off the compressor and switch to electric strip heating when it is to cold outside. Geothermal heat pumps don't cost more than electric heat. Air units are cheaper in mild winter temperatures and the same as electric heat with very cold temp's outside. When comparing cost of an electric heat pumps to gas or oil heaters you must know the cost of oil, gas and electricity is in your local, as the prices vary wildly in different regions, for you to know which is cheaper to operate.

Sure.

If heat pumps replace resistance heaters they always have a higher energy efficiency.

This says nothing about economic efficiency however. Natural gas or petroleum is much cheaper per unit of energy than electricity. Therefore using these can be much cheaper.

Simple ventilation heat exchangers can also be more efficient in terms of energy, not just in terms of economy.

I switched over to a warmth Pump final summer season. Our electric powered costs wee decreased by utilising the means employer through warmth pump. We went from 13 cents in line with kw to 6.5 cents in the process the summer season. I definitely have a extreme effective gs furnace with a v/s blower that operates as my backup whilst the temperature drops under 28 tiers. Our ordinary costs of heating and cooling dropped.

If their source if used up, or they are broken. Heat pumps are far more efficient than gas heaters because they move and compress existing heat rather than create it. The only time there is a problem is when the heat source isn't large enough to support what it being heated.