{"id":547232,"date":"2025-06-05T11:18:29","date_gmt":"2025-06-05T15:18:29","guid":{"rendered":"https:\/\/www.finehomebuilding.com\/?p=547232"},"modified":"2025-06-13T14:28:20","modified_gmt":"2025-06-13T18:28:20","slug":"one-system-wonder","status":"publish","type":"post","link":"https:\/\/www.finehomebuilding.com\/2025\/06\/05\/one-system-wonder","title":{"rendered":"One-System Wonder"},"content":{"rendered":"

I\u2019ve had my eye on Stiebel Eltron\u2019s new WPL A2W<\/strong><\/a> (air-to-water) heat pump for some time now, so I made a point to stop by the booth at IBS and take a look in person. Air-to-water heat pumps extract heat energy from the air and transfer that energy to a water\/glycol loop, allowing the outdoor unit to send heated or cooled water into an indoor tank via plumbing supply lines. Air-to-water heat pumps have been in use for decades in Europe and Asia and have recently landed in North America.<\/p>\n

These units don\u2019t require refrigerant lines to be run into a home\u2014the entire system is factory-charged and self-contained within the \u201cmonobloc\u201d outdoor unit. The WPL A2W units also deliver impressive efficiencies: They can create 149\u00b0F hot water at 175% efficiency at \u20134\u00b0F and up to 424% efficiency at 47\u00b0F (meaning the system provides up to 4.24 units of heat for every 1 unit of electricity). Depending on how they are set up, these units are able to supply all of a home\u2019s domestic hot water for cooking, showers, and other uses while also providing all of a home\u2019s heating or cooling.<\/p>\n

One of the most exciting features is the all-in-one indoor-appliance solution. The HSBC 300 Integral indoor unit<\/strong><\/a> contains two tanks stacked on top of one another, one for space heating and cooling and one for domestic hot water. The attractive white appliance also contains the system controller and all the necessary pumps, valves, and diverters for a plug-and-play solution, avoiding the external pumps, tanks, and controllers required by other systems I have seen.<\/p>\n\n\n\n
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Photo courtesy of the manufacturer.<\/figcaption><\/figure><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

It\u2019s great to see the impressive efficiencies and space-saving design all in one unit that takes care of a home\u2019s first and second largest sources of energy usage: space heating and domestic hot water. I think these products have a big future in North America. The MSRP on a WPL 25 A2W Premium 50.4-kBtu-per-hr. heating \/ 4.09-ton cooling unit is $8700. Go to stiebel-eltron-usa.com for more product info and to find out where to buy one.<\/p>\n

\u2014 Joshua Salinger; builder and business owner in Portland, Ore.<\/em><\/p>\n

From\u00a0Fine Homebuilding<\/em>\u00a0#332<\/a><\/p>\n

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