Whole-Home Backup Customer Expectation Setting

Purpose

"Whole home" is a phrase from a brochure, not a specification, and almost every unhappy backup customer is unhappy about the distance between the two. They did not expect the lights to blink and every clock to reset. They did not expect the range and the water heater to be off. They did not expect three days of propane when they had pictured a week, or a set that exercises itself at seven on a Saturday morning under their neighbour's bedroom window.

None of that is a technical failure. All of it is a scoping failure, and it is cheapest to fix before the deposit, in writing, function by function. The record this procedure produces is also what an installer, a service technician and the next owner read to find out what was actually promised.

Scope

Covers the pre-sale and pre-install expectation-setting conversation for a permanently installed backup system at a dwelling or small commercial building, engine generator or battery energy storage, under NEC Article 702.

Does not cover the technical circuit selection and its tally, owned by the critical load panel design SOP, which this conversation feeds; the operating safety briefing for a cord-connected portable set, owned by the portable generator safety briefing SOP; or the commissioning demonstration, owned by the standby generator installation and automatic transfer switch commissioning SOPs.

Roles and responsibilities

Procedure

1. Start from their last outage, not from your product line. Ask how often the power goes out, how long the worst one lasted, what actually failed, and what they were doing about it. Acceptance: outage frequency and worst duration in the customer's own words, the specific failures they name, and any medical or business dependency written down. Wrong looks like a conversation that opens with equipment; stop rule, a named life-sustaining medical dependency stops the standard path, because an optional standby system is never the sole plan for one, and that sentence goes on the record. Hazard: none, and this is the step that decides whether the rest of the conversation is about the right problem.

2. Convert "whole home" into a function list and state the transfer gap out loud. Write the functions they want carried, then say plainly how long the house is dark between the utility failing and the backup carrying load, reading the number from the product's own specification rather than from a brochure adjective. Acceptance: a function list in priority order, and the transfer gap stated in seconds for an engine set or in the product's stated fraction of a second for a storage system, written on the record. Wrong looks like a customer who learns at commissioning that an engine set takes long enough to reboot every computer, clock and network device in the house; stop rule, a customer who cannot accept the gap on an engine set is shown storage or a hybrid, not sold the engine set anyway. Hazard: none, and the gap is the single most common surprise on this work.

3. State duration in the source's own units and do the arithmetic in front of them. An engine on utility gas runs as long as the gas utility holds; on propane it runs until the usable volume in the tank is gone; storage runs until the usable energy is gone, which is a different question from how much it can carry. Acceptance: for propane, tank capacity, fill fraction, the reserve the supplier requires and the manual's consumption at the expected load, worked through to hours and days on the record; for storage, usable kilowatt-hours divided by the measured load in kilowatts, worked through to hours. Wrong looks like a runtime taken from a brochure at an unstated load; stop rule, a computed duration that falls short of their worst outage goes back to tank size, a second tank, a refill plan or a different source, decided now rather than during a storm. Hazard: none in the arithmetic, but a small propane tank's vapor withdrawal rate depends on its wetted surface and the ambient temperature, so the tank's vaporization capacity at the local design temperature is confirmed with the propane supplier and not assumed from its gallons.

4. Name what the system will not do, and have them initial each one. Go item by item: electric range, electric water heater, central air conditioning, second refrigerator, EV charging, well pump running simultaneously with everything else, and any motor that will need a soft starter to start at all. Acceptance: each exclusion written in plain room language and initialed separately, with the reason beside it, and any load they insist on either engineered in with the calculation re-run or recorded as declined advice. Wrong looks like a single blanket exclusion paragraph initialed once, which the customer will honestly not remember; stop rule, an insisted-on load that the source cannot carry is quoted as its own change rather than absorbed. Hazard: none in the conversation, but a system routinely driven into overload trips during the emergency, which is the failure they will describe to everyone they know.

5. State the ongoing obligations before the sale, including the ones they will hear. Cover the weekly or monthly exercise run and let them choose its day and time, the annual loaded test, the fuel or battery replacement interval, and what the manufacturer's warranty requires of them. Acceptance: exercise day, time and duration chosen and written down; the annual test named as a recurring visit; the maintenance items that carry warranty conditions listed. Wrong looks like an exercise timer left on its factory schedule, which is how a customer discovers their generator at dawn on a weekend; stop rule, a site where an exercise run at any hour will disturb a neighbour gets that raised now, because the fix is siting and it is free before the pad is poured. Hazard: none, though the exercise run itself carries the exhaust and clearance rules the installation SOP enforces at siting.

6. Present two or three real options against their list, with what each one gives up. Put them side by side rather than describing them in sequence, because a customer comparing is a customer making a decision rather than accepting one.

   Option	Carries	Gives up
   Engine set, whole panel	Everything on the list including large motors, for as long as fuel holds	A transfer gap in seconds, noise, exercise runs, fuel logistics
   Engine set, critical load panel	The ranked list, on a smaller and quieter set	The excluded circuits, permanently
   Storage, critical load panel	The ranked list with no gap and no noise	Duration, which is set by usable energy rather than by fuel

   Acceptance: the options presented with each row's figures filled in from steps 2 and 3 for this house, and the customer's choice recorded with the reason in their words. Wrong looks like a table of generic marketing claims; stop rule, an option whose numbers you have not worked for this house does not go on the table. Hazard: none, and an honest comparison is what stops the second-guessing that follows a single-option quote.

7. Sign the record and make it the governing document. Print it, sign it, and reference it by date on the estimate, the install packet and the commissioning record so the same list travels through the job. Acceptance: signed record filed, its date written on the estimate, and a copy given to the customer that day rather than mailed later. Wrong looks like a conversation everybody remembers differently; stop rule, no signed record, no order. Hazard: none. What the shop banks from this is a dated record of what was said and initialed; what it settles about anyone's legal position is a question for your own attorney, and that distinction is worth keeping straight.

The record this produces

One expectation record per opportunity, dated and signed before equipment is ordered.

Header: date, everyone present, outage history in the customer's words, any medical or business dependency. Body: the priority function list; the stated transfer gap with its source; the duration arithmetic shown line by line; the exclusions list with individual initials; the exercise day, time and duration; the maintenance obligations. Footer: the option comparison with this house's figures, the choice and its reason, signatures.

The installer reads the function list to build the critical load panel. The commissioning technician reads the exclusions to know what should be dead during the transfer test. The service technician reads the duration arithmetic three years later when the customer says the system used to last longer, and can show them what changed.

Worked pass: 22 kW set on propane, rural four-bedroom

Step 1: outages four to six times a year, worst was 58 hours after an ice storm two winters ago. The well pump and the freezer are what they actually care about. No medical dependency.

Step 2: function list is water, cold storage, heat, sump, kitchen lighting and the network. The engine set's stated transfer time is read off the product specification and written down; the customer accepts that clocks and the router will restart.

Step 3 fails. The existing tank is 250 gallons. Filled to 80 percent that is 250 times 0.80, or 200 gallons, and the supplier requires a reserve of 20 percent of capacity, or 50 gallons, so the usable volume is 200 minus 50, or 150 gallons. The manual's consumption table gives 2.1 gallons per hour at the load this house is expected to place on the set. That is 150 divided by 2.1, or 71.4 hours, which is 2.98 days. The customer had pictured a week, and their own worst outage of 58 hours already sits inside 71.4 hours by only 13.4 hours.

The stop rule fires and the options go back on the table: a larger tank, a second 250-gallon tank, or a written refill plan with the supplier. They choose a second tank, which doubles usable volume to 300 gallons and gives 300 divided by 2.1, or 142.9 hours, which is 5.95 days. The propane supplier is asked in writing to confirm the vaporization capacity of the tank pair at the local winter design temperature, because two tanks add volume and only help vaporization if both are connected to draw vapor.

Step 4: range, electric water heater, central air conditioning and the shop compressor are listed and initialed one at a time. The customer pushes back on air conditioning; it is quoted as its own change with the calculation to be re-run, and recorded as pending rather than promised.

Step 5: exercise moved to Wednesday at 10 a.m. for 20 minutes without load, because the nearest bedroom window belongs to the neighbour and mornings mid-week are the least disruptive.

Step 6: the three options are filled in with this house's figures, including the corrected 5.95 day duration on the engine rows. The customer picks the engine set on the critical load panel, and the reason recorded in their words is that they want the well pump to start without thinking about it.

Step 7: signed the same day, referenced by date on the estimate.

References

• NEC (NFPA 70) Article 702 for optional standby systems and 702.7 for the sign at the service equipment; confirm the adopted edition
• Manufacturer's specification and operation manual for the transfer time used at step 2 and the fuel consumption table used at step 3
• The propane supplier's own fill, reserve and vaporization-capacity figures for the specific tank at the local design temperature, which are site data and not general values
• See related: the critical load panel design SOP, which consumes the function list, and the standby generator installation and commissioning SOP, which consumes the exclusions list at its transfer test