Vedic homes are not built near harmful electro-magnetic fields caused by such things as high-tension lines and microwave towers. Special precautions are taken, including shielding of all electrical wiring, in order to ensure that electro-magnetic fields are not propagated within the home. Ideally, all materials and appliances in Maharishi Vastus should be pure and healthy. Increasing numbers of Vastu homes are being constructed with environmentally friendly, sustainable technologies, which more completely align the buildings with Natural Law. This includes growing numbers of buildings with small or zero carbon footprints. They use such technologies as solar hot water, photovoltaic electrical power, geothermal, daylighting and rainwater catchment.