Water Heater Repair & Installation — Duluth, Superior & the Northland

The orphaned water heater problem

This is the Twin Ports issue most homeowners have never heard of, and we find it constantly.

Older houses commonly had a natural-draft furnace and a natural-draft water heater sharing one masonry chimney. The furnace produced most of the exhaust volume and heat, and that kept the flue warm enough to draft properly. Then the furnace was replaced with a high-efficiency condensing unit that vents out a sidewall in PVC — and the water heater was left alone on a chimney sized for two appliances.

A small water heater cannot warm that much masonry. The flue stays cold, draft never establishes, and exhaust spills back into the basement instead of going up. In a tight house with a bath fan or dryer running, it can be actively pulled down the chimney. That is carbon monoxide entering the living space.

The fixes are known: line the chimney down to a correctly sized flue for the single appliance, switch the water heater to a power-vent or direct-vent model that vents out a sidewall on its own fan, or move domestic hot water onto an indirect tank off the boiler. Which one is right depends on the house. What is not acceptable is leaving it.

If your furnace has been upgraded in the last twenty years and your water heater still vents up the old chimney, ask us to look at it. We test draft and spillage as part of any combustion work.

Tank, tankless, heat pump or indirect

Standard tank. Cheapest to install, simplest to service, 10–15 years typical life. Still the right answer for many households, especially where the install budget matters more than operating cost.

Tankless. Endless hot water, wall-hung, 20-year potential life. In this climate, understand the incoming water temperature: Lake Superior-fed and deep-well water arrives very cold in winter, and a tankless unit's flow rate at a given temperature rise drops accordingly. A unit sized on a mild-climate chart will disappoint in a Duluth February. They also usually need a larger gas line and new stainless venting, which is why the installed cost is higher than the box price suggests.

Heat-pump (hybrid) water heater. Two to three times the efficiency of electric resistance, and rebate-eligible through Minnesota Power and Focus on Energy. The catch in this climate: it pulls heat from the surrounding air, so in a heated basement it is effectively stealing from your furnace in winter. In an unheated or marginally heated basement its efficiency drops when you want it most. It works well in the right basement — ideally a large one with some incidental heat gain — and we will be straight about whether yours qualifies.

Indirect off a boiler. If you already heat with a boiler this is often the best answer: a well-insulated tank heated by the boiler, no separate combustion appliance, no separate venting, excellent recovery rates, and it retires an orphaned chimney problem at the same time.

Hard water and the maintenance nobody does

Much of the well water in the surrounding townships — Douglas County, the St. Louis County rural areas, Carlton County — is hard, and hard water shortens water heater life by scaling the tank bottom or the heat exchanger.

Flushing the tank annually removes sediment before it insulates the burner from the water and cooks the bottom of the tank. On tankless units, periodic descaling is not optional maintenance, it is the difference between a twenty-year appliance and a seven-year one. If you are on a hard well and installing tankless, plan on a scale filter or softener and budget for descaling.

The anode rod is the other item. It is a sacrificial metal rod that corrodes so the steel tank does not; once it is consumed, the tank begins to rust. Checking it at five or six years and replacing it costs a fraction of a new water heater and can add years of life.