Your home is a system in itself, but there are several other systems that are an integral part of the whole.
These include, but may not be limited to an electrical system, plumbing, heating, air conditioning, ventilation, communications and security. Each has to be considered, and planned for, when you build your new home. The overall building envelope is a system as well, although a passive one.
The electrical system is perhaps the most important to the functioning of your home.
Virtually none of the other active systems can operate without it. When planning your electrical system, you must consider all the other systems that will rely on it. One of the first steps is to determine the load you will be placing on it. This link will take you to a table showing the typical demand of common household equipment. Remember, that not every item will be in service at the same time. A cabin or outbuilding may get by on a 60 or 70 amp service rating. Allow for at least 30 circuits. With a small house a 100 amp service is probably adequate. Large houses will need at least a 200 amp service. Local codes may not allow the lowest ratings in a house.
Most of your circuits will be 15 amp at 120 volts. Some higher amperage and voltage circuits may be required for kitchens, heating appliances, ranges and dryers. Most codes now require arc fault beakers in circuits that include bedroom receptacles. These are expensive, so plan your bedroom wiring to minimize the number you will need.
When planning, do not forget to allow for extra plugs for office or computer areas. Allow for service to air conditioners, furnaces, ventilators, and exhaust fans. Don’t forget your sump pump. If you are installing a hot water circulating pump it will require electricity. You might want to provide a plug for an electric welder in your garage.
Codes may only require one outlet in a garage, but I find this a little ridiculous. I usually plan for many more. Wire for garage door openers, even if you do not plan to install them immediately. Under eave plugs are handy for Christmas lights.
Codes often call for only one outdoor plug, but I think you will appreciate more, one at the back as well as one at the front. Larger houses should have more. Only the one needs to have a separate circuit, but all need to be GFIC. Don’t ignore the deck or patio area. Plan for sub services that may be needed, such as for a detached garage or other outbuilding. Allow for your security system.
Wiring for low voltage applications, such as door bells and thermostats, needs to be planned. If you are off grid, or planning to supplement your electricity usage with solar or wind, things become considerably more complicated and beyond the scope of this article.
Your communication systems need wiring as well. Plan possible satellite dish locations, land line connections, and possible radio antennae. Once again, don’t neglect office, entertainment or computer areas. Doubled runs of both category 5 telephone cable, and the best quality co-ax cable is a good practice. It is best if each run originates in a distribution box, similar to your electrical wiring. Perhaps you will want speaker wiring to different parts of your house or to the patio.
Security systems can be done by wireless, but permanent wiring is a little more dependable, and requires less maintenance. You may need low voltage wiring, a house wiring connection and video cable. Plan the location of surveillance cameras, motion detectors, monitors and telephone connections. Be certain that control panels will not be visible from windows.
Plumbing systems brings you fresh water and removes waste water. While not as complex as your electrical wiring, the possible designs are not quite as flexible. Getting the water to your various appliances and fixtures is fairly straight forward. For the most part you simply have to get it there in sufficient quantity to do the job. There are two sides, the hot water and the cold. Decide if you wish to use a circulation system on your hot water. Familiarize yourself with the codes pertaining to hot water safety.
Your main plumbing runs will be ¾ inch pipe to start and reducing to ½ inch. A good method is to use a ¾ inch manifolds and run ½ to each application. Don’t run ¾ to far from your water heater, if it isn’t part of a circulation system, or it will take too much time to get hot water to the application. This wastes water and energy.
Plan for a cold connection to your refrigerator and toilets, and a hot one to the dishwasher. Pex or copper piping is commonly used today. Sizes are inside diameter. Metric conversions are 13mm and 19 mm for ½ and ¾ inch respectively.
Don’t skimp on valves to isolate applications or components of your system. They make repairs and replacements much easier and less disrupting.
Waste water installations must follow rules of physics as well as health and safety regulations. All connections require traps and venting to prevent sewer gases from entering the house. Plan for clean outs at the bottom of each vent stack and at 90 degree turns. Special methods are needed to vent a sink or dishwasher located in an island cabinet. Provide for drains on high efficiency furnaces and air conditioner coils.
Codes may require a device to prevent back flow where the sewer exits the house. It is a good idea in any case.
For wastewater, ABS or PVC pipe is commonly used in sizes from 1.25 to 4 inches (32 mm to100 mm).
Many jurisdictions will not allow a sump pump connection to the waste water system. A provision will have to be made to connect to a storm sewer or to daylight.
Plumbing basics link
I have covered heating systems in a previous article that I have linked to here. Plan the locations of your warm air vent and the cold air returns for the best distribution pattern if using a forced air system.
Modern tightly sealed houses require ventilation for maintaining air quality, and for humidity control in many climates. Heat recovery ventilators can be a good investment in cold climates. Allow for the locations of vents, ducting, and for the ventilator itself. Exhaust fans will be required in the kitchen and bathrooms to vent excess moisture and odors.
There are minimum clearances required between exterior terminations and service connections as well as between outlets and inlets.
If you do not use forced air heating, then you may need ducting for air conditioning. A ductless mini-split system is an alternative, but allowances may have to be made for drains.
I have only briefly covered the active systems in a house in this article. It is primarily meant as an aid to planning, but I will try to get into more detailed discussions of each system in future posts.