p>We haven't seen any great results when trying to marry <strong>solar air heaters</strong> to an <strong>HRV</strong>. To achieve a similar result of <strong>pre-heating air</strong> before it enters the <strong>HRV</strong> I would instead propose a ‘<strong>ground loop</strong>’ system which is a solution sometimes applied to help achieve <strong>Passive House certification</strong>. It is a matter of laying a tube around the perimeter of the home (below frost-depth, or below the slab or below the skirt insulation), so that incoming air takes advantage of ambient ground temperature.</p> <p>There are some concerns with it to ensure safe air quality, here is a previously asked about<a href="/discussions/4012/possiton-of-heat-exchanger-for-ground-loop-on-hrverv/" target="_blank"> <strong>how to install a ground loop with an HRV</strong></a> that discusses those issues. And, assuming it is done correctly - </p> <p>I think you would notice better results with this technique as it not only warms incoming air in the winter, but also helps cool incoming air in the summer. The benefits of a ground loop would be 24/7, 356 days a year, while the benefits of a solar panel would be limited to sunny winter days. So you may actually see more returns from a ground loop; and it would be cheaper and easier install, and there would be no maintenance costs.  </p> <p>As for your solar water heater ‘heat storage battery’, you already have that – the concrete floor. Assuming you have at least 3 or 4 inches of concrete in your floor, it will most likely absorb as much solar-generated heat as you could possibly throw at it during a sunny winter day, so I would personally skip the step of including a separate thermal battery and feed the heat directly into the floor.  Here are a few pages that may offer you some ideas and inspiration. </p> <ul> <li><strong><a href="/guides/2208/thermal-batteries-all-about-storing-solar-heat/" target="_blank">Understanding thermal batteries</a></strong></li> <li><strong><a href="/guides/3368/solar-air-heated-radiant-floor/" target="_blank">Solar air heated floor</a></strong></li> <li><strong><a href="/guides/2205/phase-change-building-materials-natural-heat-storage-in-buildings/" target="_blank">Phase-change building materials</a></strong></li> </ul> <h3>It's also useful to read our guide on <strong><a href="https://www.ecohome.net/guides/3804/how-to-handle-a-power-outage-in-cold-weather/" target="_blank">how to survive a power outage in cold weather</a></strong></h3