From: johnbartley@email.com
Newsgroups: alt.hvac misc.consumers.house alt.home.repair
Subject: Re: AFUE, HSPF and COP, how do they relate?
Date: 20 Feb 2005 18:18:40 -0800
   posting-account=XmJhQhMAAACRio4pIup7JBLhYUtE7e2nzGzNVpXgUnH9wk1293KAkQ

Here's another rule of thumb:

"Around 37 F many heat pumps reach what is called the balance point. At
or near this temperature the heat pump needs to run constantly to
produce enough heat to maintain a comfortable indoor temperature."
http://www.askthebuilder.com/294_Heat_Pumps_-_How_Well_Do_They_Work_.shtml