Triple-Integrated Heat Pumps In 1989, Popular Science magazine gave one of its top-ten "Best of What's New" awards to the Carrier Hydrotech 2000 — a sophisticated "triple-integrated" heat pump that provided yearround high-efficiency water heating in addition to high-efficiency space heating and cooling. Unfortunately, Hydrotech's high price tag (roughly $7,000) was too much for the market to bear and Carrier withdrew the system from production in 1993. Now three manufacturers have revived the concept with less expensive systems. The Nordyne Powermiser is an airsource system and the other two — the Hydroheat, manufactured by HydroDelta Corporation, and the Hydro-Temp, produced by Hydro- Temp Corporation — are both ground-source systems. All have special refrigerant circuits that allow high-efficiency, year-round water heating, regardless of