What to check before you buy the house

Nothing in this house was designed around a heating system as we would fit one now. Whatever is there arrived later, probably more than once, and it went where it could rather than where it should.

• Ask what the ductwork actually is and where it runs. Retrofitted duct in an old house is usually undersized, particularly the return.
• Ask about the envelope. Insulation and air sealing decide more about comfort here than the appliance does, and they are the cheaper thing to improve.
• If there is original pipe or boiler insulation, have it identified by somebody qualified before anyone disturbs it. That is a specialist question, not a heating one.
• Expect the cooling question to be separate. If there are no usable ducts, adding cooling is a project rather than a connection.

The era when central heating was designed in from the start, which is good, and when the ductwork went wherever was cheapest, which is the part you inherit.

• Ask whether the ductwork is original. In most of these houses it is, and it has been carrying its second or third appliance.
• Ask for static pressure to be measured. Original ducts and modern equipment are frequently a poor match, and this is the one number that proves it.
• Check the return sizing. Undersized returns are the single most common inherited fault in this age of house.
• Look at where the ducts run. Anything in a crawlspace or an unheated attic is costing money every day.

Flexible duct in attics became normal, and the equipment is usually on its second generation. The question is whether anybody looked at the distribution when the equipment changed.

• Ask when the equipment was replaced and whether the ducts were touched. Usually the answer is yes and no, in that order.
• Have the attic runs looked at for crushing against trusses, sagging between straps and torn outer jackets. These faults are visible and they are common.
• Ask for the service records. Twenty-five years of a system’s life should have left some paperwork.
• Check the flue arrangement if the appliance was upgraded — a high-efficiency appliance venting into an old chimney is a red flag.

Tighter and better built, and the equipment may still be original. The questions move from condition to configuration.

• Ask whether the system was ever commissioned and for the figures. New does not mean set up.
• Ask about the warranty and whether it transfers. Many do, some require registration, and it is worth establishing before you own it rather than after.
• Ask about ventilation. A tight house does not shed moisture and stale air by accident, and whether anything was fitted to do it deliberately is worth knowing.
• Check for condensation history at windows and in closets on outside walls. In a tight house that is a ventilation signal.

• Insist on a heat exchanger inspection as a specific item. It is the one fault that ends an appliance outright, and a general inspection will not cover it properly.
• Ask for the data plate — model, serial and input rating. It tells you the real age regardless of how clean the cabinet looks.
• Ask for static pressure and the filter size, and check you can physically reach the filter.
• Check the flue type: a metal pipe into a chimney and two plastic pipes through a wall are different appliances with different lifespans.

• Ask about circulators, zone valves and the expansion vessel. That is where boiler faults actually live, and all three are serviceable items.
• Ask whether the system holds pressure. A system that needs topping up regularly is losing water somewhere, and finding out where is a real job.
• Walk the house and feel every emitter. A cold radiator is information and it is free to collect.
• Price the cooling separately. There are no ducts, so air conditioning is a new system rather than an addition.

• Establish where the tank is before anything else — basement, outside, or buried. The three are different purchases.
• Ask for burner service records. Oil appliances need a genuine annual service and the paperwork tells you whether they got one.
• Ask about the chimney or vent and when it was last inspected. On older oil appliances the chimney is frequently older than the burner.
• Ask what the annual consumption has been. Deliveries are recorded, and the figure is a better guide to the house than anything on the listing.

• Ask what the back-up heat is and how it is staged. Electric resistance back-up running more than it should is silent and expensive.
• Ask to see winter electricity bills, not summer ones. That is where a badly configured heat pump shows up.
• Check the outdoor unit’s mounting. In this climate it should be well up off the ground with clear space beneath it to drain.
• Ask about the electrical supply and panel if you are thinking of changing anything later.