Boiler, heat pump or furnace? What Valley homes actually have

How to tell what heats your home

The quickest way to identify your system is to look at how heat is delivered. If you have radiators or baseboard convectors that warm up, or warm floors, you have a hydronic system driven by a boiler, and the water side of that is a plumber's work. If you have vents blowing warm air, you have forced-air heat, which means a gas furnace or a heat pump, and that is HVAC territory.

Most Tempe homes are the second kind. A heat pump, which also provides cooling, and a gas furnace both push warm air through ducts and vents. If that describes your home, a boiler is not what you have, and a heating problem is a call to an HVAC contractor, not a plumber.

Why boilers are rare here

Boilers and radiators earn their keep in places with long, hard winters, where steady radiant heat through a cold season is worth the system's cost and complexity. Tempe's winters are mild and short, so builders reached for simpler, cheaper forced-air heat that also pairs with the air conditioning every Valley home needs. The result is a housing stock where a residential boiler is genuinely unusual.

Where they do turn up is specific: older custom and higher-end homes built with radiant or hydronic heat, small commercial and multifamily buildings with boiler loops, and the heating side of pools and spas. If you have one of those, hydronic service is a real need, and a plumber who works the water side is the right call.

It is worth explaining why the water-versus-air distinction is so clean a test in practice. A hydronic system is a closed or semi-closed loop of water with its own pump, expansion tank and pressure-relief controls, everything a plumber is trained to service, whereas a furnace or heat pump moves air across a heat source and belongs to the HVAC trade. Nothing about the two overlaps except the goal of a warm house, which is exactly why calling the right trade the first time saves a wasted service fee. If you are unsure, describing how the heat reaches your rooms over the phone lets us tell you immediately whether it is our job or an HVAC call.

When a plumber is the right trade

The dividing line is water versus air. If your system moves heated water, radiators, baseboard, radiant floors, boiler loops, the pumps, expansion tanks, relief valves and the water itself are plumbing, and our hydronic service covers them. Hard water matters here too: any make-up water or heat exchanger fed with untreated Valley water collects scale, the same problem that affects a water heater.

If your system moves heated air, a furnace or heat pump, that is an HVAC contractor's job, and we will tell you so plainly rather than charge to look at the wrong equipment. Being honest about that division is part of not wasting your money on a service call to the wrong trade.

For the minority of Valley properties that do run hydronic heat, there is a Tempe-specific maintenance note. Any water introduced into the loop as make-up carries the same heavy mineral load as the rest of the city supply, so an open or frequently topped-up system will scale its heat exchanger over time much as a water heater does. A well-sealed closed loop that rarely needs make-up water largely sidesteps this, which is why checking for and fixing small loop leaks, rather than just topping the system up, is part of keeping these systems efficient here.

If you do have a hydronic system

For the homes and buildings that genuinely run hydronic heat, the common service points are predictable: the circulator pump that moves the water and fails silently when it seizes, the expansion tank that absorbs pressure changes and waterlogs over time, air trapped in the loop causing cold spots, and scale on any heat exchanger fed with untreated water. The safety and pressure-relief controls matter most of all, because a neglected boiler tends to lose them.

A closed hydronic loop suffers less from Tempe's hard water than an open system, but any make-up water still introduces scale, so treatment and periodic service keep these systems safe and efficient. If you have radiant or hydronic heat, that water-side maintenance is exactly what a plumber provides.