Lighting Retrofit ROI: How to Calculate Payback and Show It in a Proposal

A lighting retrofit ROI calculation should do more than show a rough energy-saving estimate. It should show the full financial case for the project, including energy savings, demand savings, maintenance savings, utility rebate impact, and simple payback. When those numbers are incomplete or inconsistent, the proposal feels weaker than it should.

This guide explains how to calculate lighting retrofit ROI step by step, what most proposals leave out, and how to present the numbers clearly for building owners, facility teams, and decision-makers. If you want a payback number that stands up in a proposal review, this is the framework to use.

If your team is still piecing this together across spreadsheets, audit notes, and proposal documents, tools like lighting audit software and lighting retrofit software can help keep the math, scope, and proposal output aligned.

Quick answer

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Lighting retrofit ROI measures the financial return of upgrading to more efficient lighting, usually LED. A complete ROI calculation includes annual energy savings, annual demand savings, maintenance savings, gross installed cost, estimated rebate, net installed cost, and simple payback. In most commercial proposals, simple payback is the number clients care about most.

What Lighting Retrofit ROI Actually Measures

ROI in a lighting retrofit context means: the net financial benefit of the project divided by the installed cost, over a defined period. Simple payback — the version most clients ask for — is just the installed cost divided by the annual savings.

But most proposals only show part of the savings picture. That's where the math gets weak.

A complete lighting retrofit ROI calculation has four components:

1. Energy savings — the reduction in kWh consumed, multiplied by the utility's energy rate. This is the number almost every proposal includes.

2. Demand savings — the reduction in peak kilowatts, multiplied by the utility's demand charge. This is the number most proposals miss entirely, and it can represent 20 to 40 percent of total savings depending on the utility tariff.

3. Maintenance savings — the elimination of lamp replacements, ballast failures, and associated labour and lift costs. LED products last 50,000 to 100,000 hours. The maintenance savings over a 5-year period are real money, especially in warehouses or facilities with high-bay fixtures requiring scissor lifts to reach.

4. Utility rebate — a reduction in net installed cost from the utility's incentive program. This does not increase annual savings, but it directly reduces payback period and improves ROI.

If your proposal only shows number one, you are undervaluing the project and making it harder for your client to say yes.

Rebate assumptions should also be checked against current program rules and product eligibility, especially where utilities require products listed through the DesignLights Consortium Qualified Products List for incentive consideration.

Finally, this only works when the underlying audit is clean, which is why many contractors move first to lighting audit software before trying to standardize quoting.

The Full ROI Calculation, Step by Step

Here is a worked example using a 10,000 sq ft commercial office building.

Existing conditions:

• 80 x 4-lamp T8 troffers (32W per lamp, 4 lamps each = 128W per fixture)

• 3,000 operating hours per year

• Utility energy rate: $0.12/kWh

• Utility demand charge: $12.00/kW/month

Proposed retrofit:

• 80 x LED troffers (40W each)

Step 1: Calculate existing annual energy use

Fixture watts x fixture count x annual hours, divided by 1,000 to convert to kWh.

128W x 80 fixtures x 3,000 hours = 30,720,000 watt-hours 30,720,000 / 1,000 = 30,720 kWh/year

Step 2: Calculate proposed annual energy use

40W x 80 fixtures x 3,000 hours / 1,000 = 9,600 kWh/year

Step 3: Calculate annual kWh savings and dollar value

• 30,720 kWh minus 9,600 kWh = 21,120 kWh saved per year

• 21,120 kWh x $0.12/kWh = $2,534/year in energy savings

Step 4: Calculate demand savings

• Existing peak demand: 128W x 80 = 10,240W = 10.24 kW Proposed peak demand: 40W x 80 = 3,200W = 3.2 kW Peak demand reduction: 7.04 kW

• Demand savings = 7.04 kW x $12.00/kW/month x 12 months = $1,014/year

This alone is 40 percent of the energy savings number.

Step 5: Calculate maintenance savings

In this building, T8 lamp life is roughly 20,000 hours. At 3,000 hours/year, lamps would need replacement every 6 to 7 years. With 80 fixtures at 4 lamps each, that's 320 lamps plus labour to replace them.

• Lamp cost: 320 x $4.00 = $1,280 Labour (2 hours at $65/hr): $130 Total maintenance event cost: ~$1,410 every 6 to 7 years, or ~$211/year annualized

• LED fixtures at 50,000+ hours effectively eliminate this cost for the first 16 years of operation.

Step 6: Calculate net installed cost after rebate

• Installed cost (fixtures + labour): $14,400

• Estimated utility incentive (example of Save on Energy Instant Discounts, Ontario, midstream): up to $1,120Net installed cost: $13,280

  
  

Step 7: Calculate simple payback

• Total annual savings = $2,534 (energy) + $1,014 (demand) + $211 (maintenance) = $3,759/year 

• Simple payback = $13,280 / $3,759 = 3.53 years

Compare that to the payback if you had only shown energy savings: $14,400 (no incentive) / $2,534 = 5.68 years.

The difference between a 3.5-year payback and a 5.7-year payback is often the difference between a project that gets approved and one that gets deferred indefinitely.

Summary Table

Item	Value
Existing energy use	30,720 kWh/year
Proposed energy use	9,600 kWh/year
Annual kWh savings	21,120 kWh
Annual energy savings	$2,534
Annual demand savings	$1,014
Annual maintenance savings	$211
Total annual savings	$3,759
Gross installed cost	$14,400
Estimated utility incentive	$1,120
Net installed cost	$13,280
Simple payback	3.53 years

On real projects, this calculation usually sits inside a wider lighting retrofit software workflow that connects site data, replacement recommendations, install cost, and final proposal output.

Lighting Retrofit Payback Calculator

The Three Numbers That Kill Proposals

These are the calculation mistakes that show up most often in the field, and each one either understates the savings or creates a trust problem with the client.

1. Ignoring demand charges

In most commercial utility tariffs across Canada and the US, demand charges represent a significant portion of the monthly bill. Some Ontario industrial accounts pay more in demand charges than energy charges. A proposal that only shows kWh savings is leaving 20 to 40 percent of the total value unrepresented. Clients who notice this gap will question the credibility of everything else in the proposal.

2. Deducting the rebate before approval

Presenting the installed cost as already net of the rebate is a liability problem. If the rebate application is rejected, delayed, or the program changes before you submit, your client will expect the original net price. Show the rebate as a separate line, clearly labelled as estimated and subject to utility program approval. Your contract price should be based on the gross installed cost.

3. Using percentage savings instead of dollar savings

"You'll save 68 percent on lighting energy" is a statement clients cannot verify. "$3,759 per year based on your current utility rate of $0.12/kWh" is a statement they can check against last month's bill. Percentage savings feel like marketing. Dollar savings at a specific rate feel like engineering. Use the latter.

A lot of these ROI errors start when teams are still pricing projects in spreadsheets. We covered that in Excel vs lighting proposal software, especially where version control and rebate tracking start breaking down.

How to Present ROI in the Proposal Itself

The calculation work happens behind the scenes. What the client sees should be clean, clear, and immediately understandable without explanation.

A strong proposal summary includes:

A one-page financial summary 

Showing current annual lighting cost, projected annual cost after retrofit, total annual savings, gross installed cost, estimated rebate, net installed cost, and simple payback in months. One table. Everything in it.

A rebate line that is clearly separated. 

Show: Gross installed cost / Estimated utility rebate / Net installed cost. The rebate is not part of the project price, it is a client benefit contingent on program approval.

An optional 10-year cumulative savings line. 

For clients who need to build an internal business case or present to a board, showing cumulative savings over 10 years puts a much larger number in front of them. $3,759 per year becomes $37,590 over a decade. Some clients need to see that number.

For larger projects or clients that need a deeper business case, it also helps to understand where investment-grade lighting audits fit compared with standard quote-stage audits.

Simple Payback vs IRR vs NPV: Which One to Use

Simple payback is what wins approvals in small to midsize commercial retrofits. It is the one number almost every facilities manager and building owner can evaluate without a finance background.

IRR (internal rate of return) and NPV (net present value) are useful for ESCO contracts, larger capital projects, or sophisticated buyers who are comparing the retrofit to other capital investments. If your client asks for these metrics, provide them. But leading with IRR in a standard retrofit proposal adds complexity without adding clarity for most buyers.

Lead with simple payback. Offer the deeper metrics if asked or if the client signals they need them for internal approvals.

Canadian and US Utility Rate Considerations

Utility rates are one of the fastest ways to make a lighting ROI calculation look weak. In Canada and the US, the real cost of electricity depends on where the building is, what rate class it is on, and how the utility bills demand, not just the energy charge per kWh. Using a flat default number across every proposal makes the savings model easier to build, but less credible when the client checks it against an actual bill.

In the US, state-by-state variation is large enough that national averages should only be used for rough screening. The U.S. Energy Information Administration publishes commercial electricity prices by state, and the spread is wide enough that a proposal built on a generic national assumption can materially overstate or understate savings depending on the market.

In Canada, the structure can vary a lot by province and utility. Ontario uses time-based pricing schedules in some cases, BC Hydro separates customers by business rate class and applies demand billing once loads get larger, and Alberta’s market still requires care because the default Rate of Last Resort only covers part of the bill and delivery charges still apply separately. That means two buildings with similar fixture counts can produce very different dollar savings.

The practical rule is simple: use the client’s actual bill or tariff whenever possible. If you cannot confirm the rate yet, show the energy rate, demand charge, and rebate assumption clearly in the proposal so the client can verify them before approval. That makes the model easier to trust and easier to defend.

Keeping the Math Consistent

One last point that is easy to overlook: every number in your proposal must reconcile.

The fixture count in the audit tab must match the fixture count in the savings calculation. The wattage used in the savings calculation must match the wattage spec in the fixture schedule. The rebate estimate in the rebate section must match the rebate line in the financial summary. The installed cost in the summary must match the line items in the installation tab.

If you need to tighten the inputs first, this guide on what a lighting audit is breaks down the site data that directly affects savings accuracy.

When a client's facilities team or a rebate program reviewer cross-checks your proposal and finds a discrepancy between sections, the entire document loses credibility. Consistency is not a nice-to-have. It is the foundation of a proposal that gets signed.

The fastest way to guarantee consistency is to use a single tool that calculates everything from the same underlying data, rather than maintaining parallel spreadsheets across audit notes, the savings model, and the Word document you are assembling the proposal in.

If your numbers are being copied between tabs, PDFs, and proposal templates, commercial energy audit software can reduce the version-control problems that often create mismatches in savings and rebate assumptions.

Frequently Asked Questions

What is a typical payback period for a commercial LED lighting retrofit?

Most commercial LED lighting retrofits achieve a simple payback of 2 to 5 years before incentives, and 1.5 to 3.5 years after utility rebates are applied. The actual payback depends on existing fixture wattage, operating hours, local utility rates, and rebate program availability. High-bay warehouse retrofits from T5 or metal halide to LED typically achieve the fastest paybacks due to large wattage reductions and high daily burn hours.

How do you calculate energy savings from LED lighting?

Calculate existing annual kWh by multiplying fixture wattage by fixture count by annual operating hours, then dividing by 1,000. Do the same calculation with LED fixture wattage to get proposed kWh. The difference is your annual kWh savings. Multiply by the utility's energy rate (per kWh) to get the dollar value of energy savings.

What is demand savings in a lighting retrofit?

Demand savings come from reducing peak kilowatt draw. Most commercial utility tariffs include a demand charge (per kW per month) based on the highest power demand recorded during the billing period. LED fixtures draw significantly less peak power than T8 or T5 fluorescent or HID sources. Multiply the kW reduction by the utility's demand charge and by 12 months to get annual demand savings. This is often 20 to 40 percent of total savings and is frequently omitted from proposals.

Should utility rebates be included in the payback calculation?

Yes, but only as a separate line item clearly labelled as estimated and subject to program approval. The rebate reduces net installed cost, which directly improves payback period. Never deduct the rebate from your contract price before the rebate has been approved by the utility.

What is a good simple payback period for a lighting retrofit?

Most commercial building owners find paybacks under 3 years easy to approve. Projects in the 3 to 5 year range typically require a stronger internal business case or board approval. Projects over 5 years are harder to move forward without significant rebate support or a specific regulatory or maintenance driver. LED retrofits from high-wattage HID sources (250W to 400W metal halide) routinely achieve sub-2-year paybacks in high-burn facilities.

How do you show lighting ROI to a commercial building owner?

Present a one-page financial summary with current annual cost, projected annual cost, total annual savings broken into energy, demand, and maintenance components, gross installed cost, rebate as a separate line, net installed cost, and simple payback in months. Put the payback callout in plain language. Avoid percentages where dollar figures are more verifiable. Every number in the summary should trace back to an audited fixture count and a confirmed utility rate.