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Investor Presentation

May 2016

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Disclaimer

This presentation contains statements that constitute “forward looking statements” under the Private Securities Litigation Reform Act of 1995. All statements

other than statements of historical facts contained in this presentation, including statements regarding our short-term and long-term growth strategies, efforts

to develop and commercialize our products, future operations, future financial position, future revenue, projected costs, prospects, plans, objectives of

management and expected market growth are forward-looking statements. These statements involve known and unknown risks, uncertainties and other

important factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or

achievements expressed or implied by the forward-looking statements. The words “anticipate,” “believe,” “could,” “estimate,” “expect,” “guidance”, “intend,”

“may,” “plan,” “potential,” “predict,” “project,” “should,” “target,” “will,” “would” and similar expressions are intended to identify forward-looking statements,

although not all forward-looking statements contain these identifying words.

These forward looking statements are only predictions and we may not actually achieve the plans, intentions or expectations disclosed in our forward-looking

statements, so you should not rely on our forward-looking statements. Actual results or events could differ materially from the plans, intentions and

expectations disclosed in the forward-looking statements we make. We have based these forward-looking statements largely on our current expectations

and projections about future events and trends that we believe may affect our business, financial condition and operating results.

The information in this presentation is current as of May 26, 2016 and speaks only as of such date. We expressly disclaim any obligation to release any

updates or revisions to any information presented herein, including any forward-looking statements, to reflect any change in our expectations or projections

or any changes in events, conditions or circumstances on which any such information or statements are based for any reason, except as required by law,

even as new information becomes available. All information and forward-looking statements in this presentation are qualified in their entirety by this

cautionary statement.

In addition to results presented in accordance with U.S. GAAP, this presentation and related tables include Adjusted EBIDTA, a non-GAAP financial

measure. We have provided a reconciliation of this measure to the most directly comparable GAAP measure, which is available in “Reconciliations” starting

on slide 20. We use Adjusted EBITDA as a measure of operating performance, because it does not include the impact of items that we do not consider

indicative of our core operating performance, for planning purposes, including the preparation of our annual operating budget, to allocate resources, to

enhance the financial performance of our business, and as a performance measure under our bonus plan. We also believe that the presentation of Adjusted

EBITDA provides useful information to investors with respect to our results of operations and in assessing the performance and value of our business.

Although we believe this non-GAAP financial measure enhances investors’ understanding of our business and performance, this non-GAAP financial

measure should not be considered an alternative to or substitute for accompanying GAAP financial measures.

The risk factors set forth in our Annual Report on Form 10-K for the year ended December 31, 2015 and filed with the SEC on March 4, 2016, pursuant to

the Securities Exchange Act of 1934, as amended, are incorporated by reference into this presentation and should be read in their entirety alongside this

presentation.

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Disclaimer

This presentation contains market data and industry forecasts that were obtained from industry publications, third party market research and publicly

available information. These publications generally state that the information contained therein has been obtained from sources believed to be reliable, but

the accuracy and completeness of such information is not guaranteed. This presentation also contains estimates and other statistical data made by

independent parties and by us relating to market size and growth, size of insulation opportunity at various types of energy infrastructure facilities and other

data about our industry. We obtained the industry and market data in this presentation from our own research as well as from industry and general

publications, surveys and studies conducted by third parties, some of which may not be publicly available. For example, this presentation includes statistical

data extracted from an off-the-shelf market research report (World Insulation - #2956) by The Freedonia Group, an independent international market

research firm, and a separate custom market research report by Freedonia Custom Research, Inc., a wholly-owned subsidiary of The Freedonia Group, or

Freedonia, which was commissioned by us and was issued in February 2014. Such data may be outdated and involves a number of assumptions and

limitations and contains projections and estimates of the future performance of the industries in which we operate that are subject to a high degree of

uncertainty. We caution you not to give undue weight to such projections, assumptions and estimates.

The Freedonia Custom Research, Inc. Report, or the Freedonia Report, represents data, research opinion or viewpoints developed independently on our

behalf and does not constitute a specific guide to action. In preparing the Freedonia Report, Freedonia used various sources, including publicly available

third party financial statements; government statistical reports; press releases; industry magazines; and interviews with manufacturers of related products

(including us), manufacturers of competitive products, distributors of related products and government and trade associations. The Freedonia Report speaks

as of its final publication date (and not as of the date of this presentation).

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Experienced Leadership Team

Donald R. YoungPresident & CEO

John F. FairbanksVice President, CFO &

Treasurer

President, CEO and member of Board of Aspen Aerogels since 2001

Prior to 2001, worked in the U.S. and abroad in a range of senior operating

roles for Cabot Corporation

Graduate of Harvard College and earned an MBA from Harvard Business

School

Has served as CFO since 2006

More than 10 years of service as a SVP of New England Business Service, in

senior financial and operating roles

Earned a B.A. in Economics from Middlebury College and an MBA from the

Wharton School of the University of Pennsylvania

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Designs, develops and manufactures innovative, high-performance aerogel insulation primarily used in large-

scale energy infrastructure process facilities

Offers a superior combination of performance and long-term value

End users save money, reduce energy use, preserve operating assets and protect workers

Global network of energy-focused distributors, contractors and engineering firms

Proven market adoption in $3 billion global energy infrastructure market

Used by 24 of the world’s 25 largest refining companies; 20 of 20 largest petrochemical companies

Initial installations in approximately 30% of the world’s 640 refineries

Installed base of >200 million sq. ft., >$500 million of product sales since 2008

Expanding capacity to meet demand

Aspen Aerogels: An Energy Technology Company

Targeted Energy End Markets

USA34%

Canada5%

Asia Pacific34%

Latin America

2%

Europe25%

Geography

2015 Product Revenue by Region

REFINERIESPETROCHEMICAL

PLANTS

POWER GENERATION

LNG & GAS PRODUCTION

OFFSHOREOIL SANDS

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Unique Technological Advantages

What are Aerogels?

Aerogels are amorphous silica

solids

Characterized by impressive

material properties

Lowest density solid -- ~97%

air

Lowest thermal conductivity

Best thermal performance of any

widely used insulation product

Reduced corrosion under

insulation

Compact design and faster

installation

High durability and fire protection

Advantages vs. Traditional

InsulationOur Breakthrough Technology

Industrially robust

Unique product form

Proprietary manufacturing

process

Patent-protected – 86 issued

and 78 pending patents owned

or co-owned worldwide

Proven Manufacturing Process

Pyrogel XT / XT-E / XTF(hot insulat ion)

Cryogel Z(cold insulat ion )

Our Aerogel Products

Step 1:

Fill fibrous batting with a liquid-solid solution

Step 2:

Extract solvents with supercritical carbon

dioxide

Step 3:

Resulting dry fiber-reinforced aerogel

blanket

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Disruptive Products with Compelling Value Proposition

Best Thermal

Performance

Two to five times better thermal performance

Broad range of applications from -200°C to 650°C

Compact Design

& Faster

Installation

High Durability

and Fire

Protection

Reduced

Corrosion Under

Insulation

Th

erm

al

Co

nd

ucti

vit

y

Temperature Range

Pyrogel XT

Traditional Insulation

Enhances plant safety

Improves reliability

Reduces major maintenance expense

50% to 80% reduced volume

Space savings

Faster installation time with improved safety and logistics

Excellent compression resistance, tensile strength, and vibration resiliency

Fire protection

Traditional

Insulation

Vapor Permeable

Traditional Insulation;

Installed on site

Transport-ready;

Supports modular construction

Hydrophobic

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End Markets & Products

Used by 24 of the world’s

25 largest refining

companies

REFINING

Installed by 20of the top 20

petrochemical companies

PETROCHEMICAL

Preferred by LNG & FLNG

for space saving design

LNG

Maximum efficiency for

power generation

POWER

Thin and durable for pipe-in-pipe applications

OFFSHORE

• Building Materials

• District Energy

• Transportation

• Footwear and Apparel

OTHER

Pyrogel®

Spaceloft®

Cryogel®

Hot Process

Applications

Cold Process

Applications

Ambient & Low

Temperature

Applications

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Global Distribution Network and Installed Base

Source: Company Management.

Distributor

Contractor

OEM

Installed Base

Installed in more than 40 countries worldwide

34 sales & marketing employees and 45 distributors

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Industry-Leading End Users

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Key Business Highlights

1) Disruptive insulation products offering superior value and performance

2) Attractive energy infrastructure end markets are the foundation

3) Substantial installed base with industry-leading end users

4) Significant growth opportunities: expanded market penetration and new products

5) 23% 5-year revenue CAGR through 2015, EBITDA positive, growing profitability

6) Protected technology platform and proprietary manufacturing capability

7) Proven, scalable business model with attractive returns

8) Experienced management team with a demonstrated track record

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Financial Overview

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Three Months 2016 Performance

Growth Supported By Third Production Line

Three Months Ended Change

3/31/16 3/31/15 $ %

See slide 20 herein for a reconciliation of net income (loss), the most directly comparable GAAP measure, to Adjusted EBITDA for the periods presented.

($ in thousands)

32,821$ 23,500$ 9,321$ 40%

26,294 18,986 7,308 38%

6,527 4,514 2,013 45%

Operating Expenses 8,285 7,259 1,026 14%

(1,758) (2,745) 987 36%

Adjusted EBITDA Add-backs:

2,410 2,184 226 10%

Stock-based Compensation 1,370 1,295 75 6%

2,022$ 734$ 1,288$ 175%

Gross Margin 20% 19%

Adjusted EBITDA Margin 6% 3%

Total Revenue

Adjusted EBITDA

Operating Loss

Depreciation & Amortization

Cost of Revenue

Gross Profit

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Annual Revenue & Adjusted EBITDA

History of Top and Bottom Line Growth

For the Year Ended December 31,

See slide 21 herein for a reconciliation of net income (loss), the most directly comparable GAAP measure, to Adjusted EBITDA for the periods presented.

($ in thousands) 2012 2013 2014 2015

63,453$ 86,094$ 102,399$ 122,518$

71,421 75,363 85,319 97,870

(7,968) 10,731 17,080 24,648

Operating Expenses 25,005 30,703 33,123 30,883

(32,973) (19,972) (16,043) (6,235)

Adjusted EBITDA Add-backs:

9,684 10,061 10,183 9,887

1,654 4,426 8,781 5,413

Other Items 2,489 3,670 119 -

(19,146)$ (1,815)$ 3,040$ 9,065$

Revenue Growth 38% 36% 19% 20%

Gross Margin -13% 12% 17% 20%

Adjusted EBITDA Margin -30% -2% 3% 7%

Depreciation & Amortization

Stock-based Compensation

Adjusted EBITDA

Operating Loss

Cost of Revenue

Gross Profit

Total Revenue

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Financial Guidance

Profitability Projected To Improve in 2016

2016 Guidance(1)2015

(in thousands, except EPS) Actual Low High

122,518$ 117,000$ 125,000$

9,065$ 11,500$ 13,000$

EPS (0.28)$ (0.16)$ (0.09)$

Shares Outstanding 22,987 23,200 23,200

Depreciation & Amortization 9,887$ 9,600$ 9,800$

Stock Compensation 5,413$ 5,200$ 5,400$

Gross Margin 20% Mid-Twenties

(1) This 2016 financial guidance specif ically excludes litigation costs and expenses of our patent enforcement actions including

at the U.S. International Trade Commission and in Germany. The amount of these litigation costs may be signif icant and the

timing of such costs w ill be diff icult to predict. We may incur other charges, realize gains or losses, incur f inancing and

interest expense, or experience other events in 2016 that could cause actual results to vary materially from this guidance.

Adjusted EBITDA

Total Revenue

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Balance Sheets

Assets Available to Support Expansion

December 31,

2015

March 31,

2016

($ in thousands)

Assets

Cash and cash equivalents 29,357$ 32,804$

Accounts receivable, net 23,207 20,624

Inventories 6,139 6,532

Prepaids and other current assets 707 1,687

Total current assets 59,410 61,647

Property, plant and equipment, net 79,539 78,322

Other assets 94 105

Total assets 139,043$ 140,074$

Liabilities and Stockholders' Equity

Accounts payable 12,745$ 10,684$

Accrued expenses 3,441 5,568

Deferred revenue 431 681

Other current liabilities 295 476

Total current liabilities 16,912 17,409

Other long-term liabilities 166 191

Total liabilities 17,078 17,600

Total stockholders’ equity 121,965 122,474

Total liabilities and stockholders’ equity 139,043$ 140,074$

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0

20

40

60

80

100

2008A 2009A 2010A 2011A 2012A 2013A 2014A 2015A 2016E 2017E 2018E 2019E

Annual Capacity(MM ft2 / year)

East Providence

Line 1

EP Line 2

EP Line 3

EP Line 1

Expansion

Statesboro, GA

Line 1 – Phase 1

Historical Projected

Capacity Expansion Plan

Nameplate Capacity(1), Year-End Effective Capacity(2), Annual Actual Production, Annual

1. Nameplate capacity represents our projected maximum sustainable annual output. The low end of the range of projected output is reflected in the graph.2. Effective capacity is the capacity at which we can operate while maintaining the quality of our products and efficiency of our operations in a given period. Actual effective capacity is also impacted

by the date within a given year on which we add the capacity.

The projected nameplate and effective capacity for the years 2016 through 2019 are based on certain assumptions that the Company’s management believes are reasonable from time to time, but these assumptions could prove to be incorrect, which could result in nameplate capacity, effective capacity, or actual capacity differing materially from the projections above.

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Key Business Highlights

1) Disruptive insulation products offering superior value and performance

2) Attractive energy infrastructure end markets are the foundation

3) Substantial installed base with industry-leading end users

4) Significant growth opportunities: expanded market penetration and new products

5) 23% 5-year revenue CAGR through 2015, EBITDA positive, growing profitability

6) Protected technology platform and proprietary manufacturing capability

7) Proven, scalable business model with attractive returns

8) Experienced management team with a demonstrated track record

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Appendices

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Reconciliation

Note: The table above presents a reconciliation of net income (loss), the most directly comparable GAAP measure, to Adjusted EBITDA for the periods presented.

Three Months Ended

3/31/16 3/31/15($ in thousands)

Net loss (1,797)$ (2,790)$

Depreciation and amortization 2,410 2,184

Stock-based compensation 1,370 1,295

Interest expense 39 45

Adjusted EBITDA 2,022$ 734$

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Reconciliation

Note: The table above presents a reconciliation of net income (loss), the most directly comparable GAAP measure, to Adjusted EBITDA for the periods presented.

Year Ended December 31,($ in thousands)

2012 2013 2014 2015

Net loss (56,142)$ (47,611)$ (66,324)$ (6,417)$

Interest expense 21,790 30,599 50,281 182

Depreciation and amortization 9,684 10,061 10,183 9,887

Loss on disposal of assets 2,489 230 119 -

Stock-based compensation 1,654 4,426 8,781 5,413

Gain on extinguishment of convertible notes - (8,898) - -

Loss on exchange of convertible notes - 5,697 - -

Debt extinguishment costs 1,379 - - -

Write-off of costs associated with postponed public offering - 241 - -

Write-off of construction in progress - 3,440 - -

Adjusted EBITDA (19,146)$ (1,815)$ 3,040$ 9,065$

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Investor Presentation

May 2016