Quick Answer
Solar thermal systems can be a worthwhile investment for off-grid living, especially for those who can take full advantage of their radiant floor heating capabilities, but their initial cost can be high.
High Upfront Costs
Solar thermal systems are typically more expensive than solar photovoltaic (PV) systems, with prices ranging from $3 to $6 per watt, compared to $2 to $3 per watt for solar PV. However, if you’re planning to install a radiant floor heating system, solar thermal can be a more efficient and cost-effective option in the long run.
Radiant Floor Heating
Radiant floor heating relies on a network of pipes or electric mats to warm up the floor, which in turn warms the space. Solar thermal systems can provide both domestic hot water and space heating through radiant floor heating, making them a great fit for off-grid homes with this type of heating system. For example, a 2-ton radiant floor heating system with a 4-element manifold can be heated with a 3.6 kW solar thermal collector array.
System Size and Performance
The size of the solar thermal system will depend on your energy needs and climate. A general rule of thumb is to size the system to meet 50-75% of your peak winter heating demand. For example, if your radiant floor heating system requires 6 kWh of heat per hour, you would need a 3.6 kW solar thermal collector array to meet 50% of that demand. By carefully sizing the system and optimizing its performance, you can maximize the benefits of solar thermal and make it a worthwhile investment for your off-grid home.
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