Alan<div><br></div><div>No it doesnt. The ASHPWH will actually increase the heating demand considerably when running in the shoulder and heating seasons. My experiences with Stiebel Eltron is that they can actually decrease the temp by as much as 6 degrees depending on the space (assuming 800ft2 if you are not using make up air). Graham Wright did some work with this relative to PH specifically a few years ago. I believe that in his study it increased the heating demand by as much a 2/KBTUFT2YR or something like that (off the cuff metrics). Although I have installed them up here in Maine they have been outside of the thermal envelope and their primary use was for summer only residents who were offsetting with PV. For your climate why dont you just use an ASHP and run it in dehumdification mode (slight cooling) in the shoulder seasons. For DHW why not LPG? You could bury the tank or not depending on the codes there. </div>
<div>c</div><div><br></div><div><br clear="all"><font color="#ff6600"><i>Christian Corson</i><br><i>EcoCor Design/Build</i></font><br><a href="http://ecocor.us" target="_blank"><font color="#3333ff">ecocor.us</font></a><br>
<a href="mailto:chris@ecocor.us" target="_blank"><font color="#3333ff">chris@ecocor.us</font></a><br><font color="#ff6600">207 930-5088 </font><br><br>
<br><br><div class="gmail_quote">On Tue, Oct 2, 2012 at 5:24 PM, Alan Abrams <span dir="ltr"><<a href="mailto:alan@abramsdesignbuild.com" target="_blank">alan@abramsdesignbuild.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
need help quantifying the (presumed) benefit of using a heat pump water heater for a new, airtight house, passive house insulation and glazing. There is no natural gas serving the site. <br><br>the cooling load is very low--the house is surrounded by tall trees--but it will have a Wash DC latent load. The trees compromise the potential of solar thermal... <br>
<br>...so the question is, does the efficiency and modest dehumidification capacity of a HP WH offset the extra heat load, compared to either a straight elec resistance WH, or bringing in propane service?<br><br>-a<br><br>
<br clear="all"><font><font><span style="color:rgb(102,0,0)">Alan Abrams</span></font><b style="color:rgb(102,0,0)"><br></b><i><span style="color:rgb(102,102,102)">certifed professional building designer, AIBD<br>certified passive house consultant, PHIUS</span></i><b style="color:rgb(102,0,0)"><br>
</b><b><font><span style="color:rgb(102,0,0)">Abrams Design Build LLC</span></font></b><font size="4"><br style="color:rgb(102,0,0)"><font><i style="color:rgb(102,0,0)">design for purposeful living</i></font></font></font><br style="color:rgb(102,0,0)">
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