A Guide to Your Home’s Plumbing, Electricity, and HVAC

This is part of our ongoing series on home maintenance basics to help you keep up your home and grow your investment with confidence.

What comes to mind when we say, “P-Trap?” Hint: It’s not a ’90s movie starring Lindsay Lohan. It’s actually an essential part of your plumbing.

What about “tripped breaker?” Nope, not a dance move. But seriously, do you know why circuit breakers trip? Or how they fit into the big picture of your electrical system?

Outlets, panels, valves, ductwork, vents, furnaces, boilers, fixtures. Your home is full of small parts that make up large systems.

We break it all down into simple terms … so you can understand what the heck it is that you’re looking at. A basic understanding can really help with solving problems!

The systems we’ll explain are:

• Electrical
• Plumbing
• Heating, Ventilation, and Air Conditioning (HVAC)

Starting with:

Your electrical system

The main idea you need to know is this: Electricity needs a complete circuit to provide power. A circuit is a circular path through which electricity follows. It begins and ends in the same place and breaks in the path interrupt the flow of electricity.

For example, a light switch breaks a circuit when the light is turned off and reconnects it again when it’s turned on. If a tree knocks down a powerline, or a rodent chews through a wire in your home, it also interrupts the circuit.

Electricity outside your home

Electricity reaches your home through a service drop, which is a set of wires that run from a transformer to your house. Transformers are those big grey boxes you see on telephone poles. They transfer energy from the power lines to your home’s individual electrical circuit. The wires may run overhead from a utility pole, or they might be buried underground.

The service drop wires attach to an electrical meter, which is usually a gray box with a glass cover attached to the side of your home. It measures the amount of energy you use, allowing the utility company to figure out your bill each month.

Electricity inside your home

From the meter, electricity passes through your electrical panel. This is also a grey box, usually located in the basement or in a utility closet. First, the electricity flows through the main breaker. That’s the big switch or switches at the top of your panel.

If you flip the main breaker off, it breaks the circuit, stopping the electricity for your entire home. This is good to know in case of emergency, like if you shut the power off for your home during a weather evacuation.

From the meter, electricity passes through your electrical panel. This is also a grey box, usually located in the basement or in a utility closet. First, the electricity flows through the main breaker. That’s the big switch or switches at the top of your panel.

If you flip the main breaker off, it breaks the circuit, stopping the electricity for your entire home. This is good to know in case of emergency, like if you shut the power off for your home during a weather evacuation.

Individual electric circuits

Below the main breaker, there are rows of smaller breakers. These breakers distribute power through the smaller circuits in different areas of your home. They may direct power to a single appliance, a few outlets, or a whole room, depending on how your house is wired.

A tripped breaker is when the breaker turns off, preventing electricity from flowing through that circuit. Breakers trip to prevent damage to your electrical system. It can happen if too much electricity flows through the circuit (powers surge) or if the wrong wires touch (short circuit).

If you lose power in a certain part of your home, check your panel. Ideally, breakers are labeled according to which circuit it controls, such as “kitchen,” “downstairs bathroom,” or “washer and dryer.” If they aren’t labeled, look for a breaker that looks like it isn’t all the way to the left or right, in line with the others. Usually, you just need to flip the breaker off and on again. If it continues to trip, call in an electrician.

The end of the electrical line

The different rooms of your home have outlets, fixtures, and switches. When you plug an appliance into an outlet or screw a lightbulb into a fixture, the circuit is connected, allowing electricity to flow to the appliance. When you shut a light switch off, it breaks the circuit to the fixture, and the light goes out.

Your plumbing system

Freshwater comes in, wastewater goes out. That’s the gist of your plumbing system. The main thing to know is that your plumbing is full of water, lots and lots of water… and even a small leak can wreak havoc.

Water flowing into your home

Water is pumped into your home through the main water line, a copper or plastic pipe typically located in the basement or utility closet.

If your home has municipal water, rather than a well, the main line will have a water meter to measure how much water flows into your home. The meter may be outside of a home in a pit between the house and the street.

Your main water line may also have a pressure valve that lets you control the water pressure flowing to your fixtures. This is usually located right near the meter and the main shut off.

Where the main water line comes into your house, you will also find your water shut-off valve. This does exactly what it sounds like: When you twist the valve into the off position, it shuts the water off for your whole house. This is one of the most important components of your plumbing system: If you have a leak, you’ll want to be able to shut all your water off before it gets out of hand.

Water flowing through your home

After water enters your home, it flows through both cold and hot water supply pipes. Hot water pipes are connected to your hot water heater. Most hot water heaters have large water storage tanks where the water heats up, though on-demand tankless heaters are becoming more common. Your hot water heater is likely located in your basement or utility closet, and it will also have a shut-off valve, a pressure valve, and a temperature control.

Supply pipes run through walls, floors, and ceilings, bringing water to fixtures and appliances, such as toilets, sinks, washing machines, and dishwashers. Fixtures have their own individual shut-off valves to stop water from flowing to them without stopping the entire system. With your toilet or sink, the shut-off is located beneath the fixture. Most likely, the shut off for your tub and shower is hidden in the wall or behind an access panel.

Water flowing out of your home

Dirty water exits fixtures and appliances down the drain where it passes through the P-trap (sometimes just called the “trap”). The P-trap is a section of pipe that is shaped like a “U” or a “P” turned horizontal. The P-trap allows wastewater to pass through, but it keeps enough water in the bend to stop sewer gasses from passing back into your home and making the place a little smelly.

After passing through the P-trap, wastewater continues through horizontal pipes to a large vertical pipe called the soil stack. The soil stack carries wastewater to the bottom-most pipe in your home, called the house drain, and allows sewer gas to vent out. The house drain carries all wastewater out of your home.

Your house drain has cleanouts on it to provide access to clear major clogs. There’s typically a cleanout where your house drain leaves your home and at roughly every 100 feet of horizontal pipe. The cleanouts found in basements are usually Y-shaped sections of pipe. Outside your home, they’re usually a pipe with a cap that sticks out of your yard. Most likely, only a plumber will handle these pipes, but it’s good to know where to find them.

Psst … having trouble keeping track of the filters and valves in this post? For help, refer to this table:

Your HVAC system

HVAC stands for heating, ventilation, and air conditioning. Your HVAC system creates the desired climate inside your home by warming, cooling, venting, and humidifying or dehumidifying the air.

There are tons of different HVAC units. We already covered cooling systems in our ultimate guide to air conditioning, so for this post, we’ll explain the two most common categories of heating systems. The basic concepts should apply to any system.

Your heat source

There are two main types of heat sources: Furnaces and boilers. Both use gas, oil, or electricity to create heat. So what’s the difference?

Furnaces, also known as forced-air systems, heat air, and use a blower fan to distribute the air throughout your home using ductwork and vents (more on this in the distribution section below). They typically have:

• A filter that needs to be changed monthly during heating season.
• An on-off switch to cut power to the unit (if it doesn’t have an on-off switch, flip the breaker to turn it off.
• A reset switch that lets you reset the motor if it malfunctions.

Boilers, technically known as hydronic heat systems, heat water and pump it through pipes to different parts of your home. Unlike furnaces, boilers don’t have filters. However, they typically do have:

• A switch that lets you turn the unit on and off.
• A temperature gauge that measures and controls the water temperature. (Check your boiler’s manual or ask an HVAC pro about the proper temperature range.)
• A pressure gauge showing the pressure levels. (Too much or too little pressure can cause problems with your system. Check your boiler’s manual or ask an HVAC pro about the proper range.)
• A relief valve through which excess pressure safely releases.

Tip: If there’s a leak from your boiler, you can stop its water flow by turning off your main water shut-off valve.

If your furnace or boiler runs on gas, there will be a gas shut-off valve on the gas line near the bottom of the unit. You may need to turn the gas off if there’s a gas leak or if you need to reset or do maintenance on your furnace.

If your heating system uses oil, it will have an oil burner that filters the oil and ignites it. Burners have a filter that needs to be replaced annually.

Note: Some newer heating systems provide both heat for your home and hot water for your sinks, showers, and appliances, eliminating the need for a separate hot water heater.

Your heating distribution

The way that heat is distributed throughout your home depends on the type of heating system you have:

• Furnaces use ductwork and vents to deliver hot air through your home. The blower fan in the furnace pushes the air through the ducts and out of the vents. Vents often have filters behind them that need to be changed every one to three months during the heating season.

Ductwork often also has dampers. A damper is a valve inside the duct that opens and closes to allow air to pass through. They’re usually operated by a small handle or a wingnut on the outside of the duct, though newer systems are sometimes remotely controlled. Dampers give you more control over your heat distribution. If you want to direct more heat to a certain air you can open the dampers, and if you want to block heat from another area, you can close them.

• Boilers deliver hot water or steam through pipes to different types of radiators, including old-school cast-iron radiators and baseboard radiators.

Many homes also have hydronic radiant heat in the flooring or walls. With hydronic radiant heat, hot water is pumped through tubes under the floor or in the walls which send heat into a room.

Regardless of the type of radiator, they work the same way. Hot water is pumped through them, the heat is transferred from the water to a room, and the cool water returns to the boiler.

Your heat ventilation

Good ventilation is crucial to keep your home comfortable and healthy. There are two main types: Structural ventilation and interior ventilation.

Interior ventilation includes things like bathroom exhaust fans, range hoods, and laundry ductwork.

Structural ventilation allows heat and moisture to escape from your attic, crawlspace, and/or basement to prevent rot, mold, and mildew. Vents are often found in roof eves and in the foundation.

… Phew! Now that we understand all these systems, these posts can help manage them:

• Overwhelmed with home maintenance? Here are 7 easy tasks any homeowner can handle.
• On a budget? Here are 5 easy home updates for under $25.