Geothermal Heating Systems for Homes

Domestic Geothermal heating systems can be a great way to heat a home, replace a furnace, and are labeled as money savers. Question is, are they worth the hype? Here's a quick view first of how they operate.

从6米到10米的深度开始，地球的温度就不再受地表温度变化的影响，而是相对稳定地保持在8到10摄氏度左右。所以地热加热和冷却的基本原理是利用地球内部的温度来平衡北美和加拿大急剧变化的地表温度。

With the use of heat pumps, geothermal heating and cooling systems extract heat energy and transfer it into buildings, saving approximately 50 to 60% on heating and cooling costs, depending on the fuel being compared to.

在夏季的几个月里，地热冷却的功能与标准的空调类似，只是热量不是简单地喷射到外面的空气中，而是沉积在地下深处以备将来使用。其结果是无内疚感的空调，因为在夏季提取的热量实际上用于温暖地下深处的地球，这些热量将在冬季提高地源热泵的效率。

Geothermal home heating systems:

Vertical closed-loop geothermal systemshave a sealed U-shaped pipe of high density polyethylene that carries a heat transfer fluid (usually a water / methanol mix) in a continuously circulating loop allowing an exchange of heat by conduction. As the liquid returns to the surface, either heated or cooled depending on the season, the additional or reduced amount of heat in the water is used to condition the home. The required depth for this system is generally 300 feet or more, and the cost is calculated by the foot. Through the nose, but by the foot.

Geothermal vertical loop system © Alexandre Gilbert

Horizontal closed-loop geothermal systemsfunction in the same manner as vertical systems, except that pipes are run back and forth 6 to 10 feet underground. Installation involves excavating trenches (at least 300 feet of them), rather than digging a well.

Horizontal ground source heat pump systems can be cheaper to install but require a significant amount of space, and it does some pretty intense damage to any ecosystems that lay in its intended path. For a given length of pipe, horizontal loop systems are a bit less efficient than vertical loop systems, as they can be more easily affected by surface temperatures. The other downside is that if or when there's a leak in the circuit, with a horizontal mat or grid style system the whole garden area has to be dug up again in search of a tiny leak that is losing the system pressure.

Geothermal horizontal loop system © Alexandre Gilbert

Open-loop geothermal systemsuse ground water pumped directly from a supply well (75 to 100 feet deep) in order to draw and inject heat. Water is pumped out of the first well, and after the heat exchange is carried out, it gets injected into the second well.

Geothermal open loop system © Alexandre Gilbert

Open-loop systems have a very high thermal efficiency and installation can be up to 50% less expensive than vertical closed loop systems. However, conditions necessary for the proper function of these systems are rarely found in urban areas, as they require an abundant source of ground water and a high water table.

Will geothermal heating save me money?

That truly depends on the size of the project to heat.No geothermal system is cheap to install, and because it offers only a reduction in consumption, the return on investment is really only viable for larger buildings. For this reason geothermal is more suited to commercial or multi-unit residential projects of substantial size.

A home would have to be quite large, and somewhat poorly-insulated to actually make it pay for itself in a reasonable time frame. In many cases, particularly with moderately-sized new homes being built, that large of a financial investment towards energy efficiency could offer much greater returns if put towards heat retention instead -better windows, additionalhome insulationin new build,insulating existing walls from the outside during a house renovation, or better用于空气密封的胶带和薄膜, etc.

Ball park pricing for a geothermal system: For an averaged size home (2000 sq. ft.) a GSHP will easily cost $30,000 to have installed, and that is in exchange for a monthly saving of about 50% on the heating bill. So payback for the average single family home is simply too far away to make this a financially competitive option with all but the highest consuming homes - and even then only when the boiler or furnace has failed and needs replacement.

That same investment of $25,000 (or perhaps less) ina better thermal envelope可能会轻松减少70%或80%的取暖费，甚至更多。Geothermal energy is an excellent global technology, but poorly insulated single family homes will get far more bang for the buck if the money is put into insulation instead, or balanced between energy saving renovations andhigh efficiency heat pumpsespecially if choosing fromthe best heat pumps in our comparison guide.

Now you know more aboutGeothermal heating for homes,learn more aboutsustainable home comfort,energy efficiencyandhow to reduce the carbon footprint of homeson the following pages and in theEcoHomeGreen Building Guidepages.

Find more aboutgreen home constructionand reapthe benefits of a free Ecohome Network Membership here.